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"direction finding" Definitions
  1. the finding of the azimuth of a distant transmitter by the use of a direction finder
"direction finding" Synonyms
steering triangulation navigation celestial navigation course plotting map reading pilotage sailing piloting manoeuvring(UK) guiding seamanship aeronautics seafaring yachting shipping steerage nautics plotting a course travelling(UK) radar sonar scanning system tracking system orienteering routing direction-finding route-planning navigational course-plotting directional route-finding More

621 Sentences With "direction finding"

How to use direction finding in a sentence? Find typical usage patterns (collocations)/phrases/context for "direction finding" and check conjugation/comparative form for "direction finding". Mastering all the usages of "direction finding" from sentence examples published by news publications.

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Even Fitbit recently found itself heading in that direction, finding a fair bit of success with the Versa.
Staff of the High Frequency Direction Finding (HFDF) Center will operate the high frequency antenna system used to protect life and property.
The phone would then act as a transmitter that they could home in on with a Triggerfish cellular radio direction-finding system that they were using.
The $5,000 maintenance purchase matches the price for maintenance work on an AmberJack direction-finding antenna, while the $2,000 prices correspond with Harpoon signal amplifier maintenance.
On Tuesday, voters overwhelmingly backed a measure that set greyhound lovers scrambling in a new direction: finding new homes for thousands of dogs with no clear future.
Ali of New York went in another direction, finding the Bandols great with Indian food and unexpectedly good with chilled shrimp served with homemade horseradish cocktail sauce.
Accurate positioning and direction finding coupled with superior sensing and imaging, just like humans use their eyes to see things clearly both near and far, will become possible with 6G.
Hastings goes in a darker direction, finding rough parity not in the validity of the goals for which the rivals fought but in their insensitivity to the staggering destruction they wrought.
With that one there was some direction finding done—similar to standard triangulation—but also people noticed that the numbers station broadcast was getting interference from Radio Habana Cuba, which tends to suggest the two signals are coming from the same site.
Radiotriangulation scheme using two direction-finding antennas (A and B) Direction finding antenna near the city of Lucerne, Switzerland Direction finding (DF), or radio direction finding (RDF), is the measurement of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication, including radar signals detection and monitoring (ELINT/ESM). By combining the direction information from two or more suitably spaced receivers (or a single mobile receiver), the source of a transmission may be located via triangulation. Radio direction finding is used in the navigation of ships and aircraft, to locate emergency transmitters for search and rescue, for tracking wildlife, and to locate illegal or interfering transmitters.
Doppler radio direction finding, or Doppler DF for short, is a radio direction finding method that generates accurate bearing information with a minimum of electronics. It is best suited to VHF and UHF frequencies, and takes only a short time to indicate a direction. This makes it suitable for measuring the location of the vast majority of commercial, amateur and automated broadcasts, and Doppler DF is one of the most widely used direction finding techniques. Other direction finding techniques are generally used only for fleeting signals, or longer or shorter wavelengths.
Orizaba and her sisters each had direction finding equipment and an echo sounding device.
Its navigation equipment included wireless direction finding, an echo sounding device and a gyrocompass.
I-19b, Page 4 The Feste also had a Direction Finding platoon, which provided resources on demand. Communications between the Direction Finding sites and the Regiment were provided by a Communications platoon, which passed results back to the NAAS via telegram or teleprinter.
The boat's electronic support measures included a direction finding system, interceptor and a radar warner.
Other wartime changes included the fitting of radar and HF/DF radio direction-finding gear.
Retrieved December 2, 2005. Another form of recreational radio direction finding activity in North America that includes the use of automobiles for transportation is most often referred to as foxhunting or transmitter hunting, but is sometimes confused with the organized international sport of amateur radio direction finding.
Captain H.J. Round devised and oversaw the construction of an array of direction finding stations that were able to track the movements of enemy ships. The use of radio receiving equipment to pinpoint the location of the transmitter was also developed during the war. Captain H.J. Round working for Marconi, began carrying out experiments with direction finding radio equipment for the army in France in 1915. Hall instructed him to build a direction finding system for the navy.
He carried out numerous Radiocommunication trainings and supported Phone-communication. First category referee in Amateur radio direction finding of Polish Assosiacion of Amateur radio direction finding, multiple referee of General Polish Championships of Amateur radio direction finding and Contests of Mermaid Cup (pol. Puchar Syreny). He carried out trainings and Contests for Scouts environments of Capital Banner, he was in charge of Radiocommunication during general events of Capital Banner – including White Service in 1999 on Piłsudski Square during Pope John Paul's II Pilgrimage to Poland.
Improved radar and direction-finding equipment improved the RCN's ability to find and track enemy submarines over the previous classes.
Due to this directional pattern, small loops are used for radio direction finding (RDF), to locate the position of a transmitter.
Her navigation equipment included wireless direction finding and an echo sounding device. The MoWT appointed Blue Star Line to manage her.
Transmitter hunting (also known as T-hunting, fox hunting, bunny hunting, and bunny chasing), is an activity wherein participants use radio direction finding techniques to locate one or more radio transmitters hidden within a designated search area. This activity is most popular among amateur radio enthusiasts, and one organized sport variation is known as amateur radio direction finding.
Arbalet-M is mentioned in Russian literature as a portable direction-finding and electronic attack system used in the Second Chechen War.
Blair 1998 p.30 Celandine carried Type 271 centimeter-wavelength radar. None of the ships carried HF/DF high-frequency direction finding sets.
The Airline used the new onboard direction finding equipment to navigate without lighter ground navigation aids over its Kansas City to Tulsa route.
Amateur radio and some cellular or PCS wireless systems use direction finding or triangulation of transmitter signals radiated by the mobile. This is sometimes called radio direction finding or RDF. The simplest forms of these systems calculate the bearing from two fixed sites to the mobile. This creates a triangle with endpoints at the two fixed points and the mobile.
The conversion retained her original boilers, but her furnaces were converted to oil burning. The ship was equipped with direction finding equipment and radio.
By 1930 her navigation equipment included wireless direction finding, and by 1934 this had been augmented with an echo sounding device and a gyrocompass.
Events hosted by groups and organizations that involve the use of radio direction finding skills to locate transmitters at unknown locations have been popular since the end of World War II. Many of these events were first promoted in order to practice the use of radio direction finding techniques for disaster response and civil defense purposes, or to practice locating the source of radio frequency interference. The most popular form of the sport, worldwide, is known as Amateur Radio Direction Finding or by its international abbreviation ARDF. Another form of the activity, known as "transmitter hunting", "mobile T-hunting" or "fox hunting" takes place in a larger geographic area, such as the metropolitan area of a large city, and most participants travel in motor vehicles while attempting to locate one or more radio transmitters with radio direction finding techniques.
Type 286 radar was fitted during 1941, later supplemented by Type 271 and Type 291, while HF/DF radio direction-finding gear was also fitted.
BFRA was the host organization for the 2006 Amateur Radio Direction Finding World Championships.International Amateur Radio Union Region 1 (2006). "Letter of Intent" . Retrieved Aug.
These two bands were chosen because of their universal availability to amateur radio licensees in all countries. Each band requires different radio equipment for transmission and reception, and requires the use of different radio direction finding skills. Radio direction finding equipment for eighty meters, an HF band, is relatively easy to design and inexpensive to build. Bearings taken on eighty meters can be very accurate.
Amateur radio direction finding (ARDF, also known as radio orienteering, radio fox hunting and radiosport) is an amateur racing sport that combines radio direction finding with the map and compass skills of orienteering. It is a timed race in which individual competitors use a topographic map, a magnetic compass and radio direction finding apparatus to navigate through diverse wooded terrain while searching for radio transmitters. The rules of the sport and international competitions are organized by the International Amateur Radio Union. The sport has been most popular in Eastern Europe, Russia, and China, where it was often used in the physical education programs in schools.
Groups were also built in Iceland, Nova Scotia and Jamaica. The anticipated improvements were not realised but later statistical work improved the system and the Goonhavern and Ford End groups continued to be used during the Cold War. The Royal Navy also deployed direction finding equipment on ships tasked to anti-submarine warfare in order to try to locate German submarines, e.g. Captain class frigates were fitted with a medium frequency direction finding antenna (MF/DF) (the antenna was fitted in front of the bridge) and high frequency direction finding (HF/DF, "Huffduff") Type FH 4 antenna (the antenna was fitted on top of the mainmast).
The WERA system provides the option to use both techniques; the compact version with direction finding or the array type antenna system with beam forming methods.
Grove, along with other ships of the 2nd Escort Group, namely , and , had sunk the German submarine . This followed a 'Huff Duff' (High frequency Direction finding) interception.
Especially with tactical aircraft, there was a gap between the knowledge of SIGINT personnel and the understanding of warfighters. For example, end users often expected a direction-finding fix to be a point, rather than an area of probability. In 1968, the next tactical improvement was the RU-21 LAFFIN EAGLE and the JU-21 LEFT JAB, the latter being the first with computerized direction finding and data storage.
Fox Oring is a variation of the sport of Amateur Radio Direction Finding. Fox Oring is a timed race in which individual competitors use a topographic map and a magnetic compass to navigate through diverse, wooded terrain while searching for radio transmitters. The term is derived from the use of the term fox hunting to describe recreational radio direction finding activity and an abbreviation of the word orienteering.
Like Amateur Radio Direction Finding, Fox Oring is a sport that combines the skills of orienteering and radio direction finding. Fox Oring requires more orienteering skills than ARDF. In a Fox Oring course, the radio transmitters put out very little power, and can be received over only very short distances, often no more than 100 meters. The location of each transmitter will be indicated on the map with a circle.
Records of his research are available in the university's archives. Hayden was later employed by Southwest Research Institute where he continued to contribute to HF direction finding technology.
As few individuals in Europe had personal automobiles at the time, most of this radio direction finding activity took place on foot, in parks, natural areas, or school campuses. The sport of orienteering, popular in its native Scandinavia, had begun to spread to more and more countries throughout Europe, including the nations of the Eastern Bloc. As orienteering became more popular and orienteering maps became more widely available, it was only natural to combine the two activities and hold radio direction finding events on orienteering maps. Interest in this kind of on-foot radio direction finding activity using detailed topographic maps for navigation spread throughout Scandinavia, Eastern and Central Europe, the Soviet Union, and the People's Republic of China.
He also performed some experiments with transmission paths over land and sea at different times of the day and investigated direction finding, for which he used a frame antenna.
FuG 141: Receiver for signals from the NS4 emergency transmitter. Fitted to air-sea rescue units. Operated with a direction finding loop. FuG 142: Receiver to receive MW beacons.
The airships relied largely on dead reckoning, supplemented by a radio direction-finding system of limited accuracy. After blackouts became widespread, many bombs fell at random on uninhabited countryside.
The First World War broke out in 1914, and Round was commissioned onto the General List and seconded to Military Intelligence with the rank of captain. Using his experience in direction finding, he set up a chain of direction-finding stations along the Western Front. These stations proved so successful that another set was installed in England. In May 1916, the stations were monitoring transmissions from the German Navy at anchor at Wilhelmshaven.
GdNA intercept station Direction-Finding day report. Direction finding (D/F) was perhaps of the greatest importance in signal intelligence activities, as it enabled the location of the enemy. Its importance increased as Russian radio discipline, code and cypher security improved during the latter half of the war.I-19b, Page 38 The Kona employed 5 personnel with each forward platoon with 50 D/F personnel stationed at Feste 10 (the long range intercept unit).
Blackmouth Cur use this method. Traditionally, the dogs were followed on foot by hunters listening to their barks, although some hunters now use radio direction finding equipment to follow the pack.
However, the technical problems of realising a seaborne high-frequency direction finding system were severe in comparison to those of a land based system. This was mainly due to the very detrimental effect of radio signal reflections from the ship's superstructure, which could cause severe errors in the required measurement of U-boat bearings. The key to an operational system was the design of an effective seaborne direction finding antenna, which was an extremely difficult task.
Elliott (1972), p. 264 A comprehensive reference on World War II wireless direction finding was written by Roland Keen, who was head of the engineering department of RSS at Hanslope Park. The DF systems mentioned here are described in detail in his 1947 book Wireless Direction Finding. At the end of World War II a number of RSS DF stations continued to operate into the Cold War under the control of GCHQ the British SIGINT organisation.
Most direction finding effort within the UK now (2009) is directed towards locating unauthorised "pirate" FM broadcast radio transmissions. A network of remotely operated VHF direction finders are used mainly located around the major cities. The transmissions from mobile telephone handsets are also located by a form of direction finding using the comparative signal strength at the surrounding local "cell" receivers. This technique is often offered as evidence in UK criminal prosecutions and, almost certainly, for SIGINT purposes.
A regulated sport form of transmitter hunting by runners on foot is called Amateur Radio Direction Finding, known worldwide by its acronym, ARDF. It is an amateur sport that combines the skills of orienteering and radio direction finding. ARDF is a timed race in which individual competitors use a topographic map and a magnetic compass to navigate through diverse, wooded terrain while searching for hidden radio transmitters. ARDF is the most popular form of transmitter hunting outside North America.
The NAAS evaluation section received raw intercepts from the D/F sections of both the FAK and the NAK. The FAK sent requests not only to the long range but also the close range direction finding sites. Fak 617, which covered the Russian 1st Ukrainian Front, for example, sent its orders both to three or four long range direction finding sites and about 12 close range units. The D/F reported back using enciphered wireless signals.
The Croatian Amateur Radio Association (, HRS) is a national non-profit organization for amateur radio enthusiasts in Croatia. Key membership benefits of HRS include the sponsorship of amateur radio operating awards and radio contests. HRS also supports local competitions in Amateur Radio Direction Finding as well as a national team that travels to regional and world championship events. HRS has been the sponsoring organization for the 2010 Amateur Radio Direction Finding World Championships held in Dubrovnik.
The AN/FRD-10 Circularly Disposed Antenna Array (CDAA) was a United States Navy circular "Wullenweber" antenna array, built at a number of locations during the cold war for high frequency radio direction finding (HF/DF) and signals intelligence. In the Joint Electronics Type Designation System, FRD stands for fixed ground, radio, direction finding. 14 sites were originally constructed as a part of the "Classic Bullseye" program. Two AN/FRD-10 systems were later installed in Canada.
The Army's air defence (PVOS, Protivzdušná obrana státu) had anti-aircraft missile units, fighter interceptor aircraft and radar and direction-finding units, known, in accordance with Soviet terminology, as radio-technical units.
Over the next several years, his work included the building of a highly advanced radio direction-finding set that used a CRT for its display; this was installed in Nova Scotia in 1938.
Ground search parties were organised at Rebiana, Bzema, and LG07, and various direction-finding stations monitored possible signals from the missing aircraft. Ground searches began based on doubtful bearings taken during the day.
Wacław Struszyński (; 1904–1980) was a Polish electronics engineer who made a vital contribution to the defeat of U-boats in the Battle of the Atlantic. He designed an exceptional radio antenna which enabled effective high frequency (HF) radio direction finding systems to be installed on Royal Navy convoy escort ships. Such direction finding systems were referred to as HF/DF or Huff-Duff, and enabled the bearings of U-boats to be determined when the U-boats made high frequency radio transmissions.
Recruits were trained in direction- finding, teletype operation, and simple field codes, and they were sent out into field units.IF-250, p. 3 No special courses were conducted in the Replacement and Training Companies.
KARL was the host society for the 14th World Amateur Radio Direction Finding Championships held in Hwaseong, Gyeonggi, South Korea in September, 2008.Korean Amateur Radio League (2008). "14th World ARDF Championships". Retrieved Feb.
Reginald Smith-Rose, October 1948. Reginald Leslie Smith-Rose CBE (2 April 1894 - 19 March 1980) was an English physicist of the National Physical Laboratory who was a world leader in radio direction-finding.
50 in machine guns in 1943. Type 286 radar was fitted early in the war, which was replaced by Type 271 in March 1942, when HF/DF radio direction-finding gear was also fitted.
During the war years, she became one of the first ships to be fitted with the new wireless direction-finding apparatus. After the squadron was retired in 1917, she was re-fitted for peacetime service.
As a result, crews began calling the mission "Lost Cause". Tactical Naval SIGINT monitored stopped Soviet transports, when it was unknown if they would challenge the naval quarantine. Direction finding confirmed they had turned around.
He was vectored by ground-control onto the intruder by Chain Home Radio Direction Finding (RDF) facilities. The RDF sent a report to the main operations room of Fighter Command Headquarters at RAF Bentley Priory.
During World War II, the cable station was once again a vital link. The Cocos were valuable for direction finding by the Y service, the worldwide intelligence system used during the war.McKay, S. 2012. The Secret Listeners.
At the airport and airship-port Rhein-Main a radio beacon was set up. The idea was to attempt a Funkbeschickung (a calibration of the direction-finding equipment). Hazy air hindered the attempts despite good weather conditions.
The secretary of the Tizard Committee, Albert Percival Rowe, coined the acronym RDF as a cover for the work, meaning Range and Direction Finding but suggesting the already well-known Radio Direction Finding. Late in 1935, responding to Lindemann's recognition of the need for night detection and interception gear, and realizing existing transmitters were too heavy for aircraft, Bowen proposed fitting only receivers, what would later be called bistatic radar.Judkins, Phil. "Making Vision into Power" , International Journal of Engineering and Technology, Vol 82, No 1 (January 2012), pp. 103–104.
The SLR-25(V)1 Advanced Cryptologic Carry-on Exploitation System (ACCES) is a portable version of the SLR-25(V)2 SSEE (Ship Signal Exploitation Equipment) without dedicated SIGINT spaces. Coupled with an AN/SSQ-120 Transportable Radio Direction-Finding system, the ACCES provides a complete SIGINT collection system. The AN/SSQ-120 has HF, VHF, and UHF antennas and direction-finding logic. More capable than the AN/SLR-25 with AN/SSQ-120 is the AN/SSQ-137 Ship Signal Exploitation System, an open-architecture system for command & control as well as intelligence.
The Mongolian Radio Sport's Federation (MRSF) (in Mongolian, Монголын Радио Спортын Холбоо) is a national non-profit organization for amateur radio enthusiasts in Mongolia. Early activities of the organization focused on radiosport, and the MRSF was active in promoting Amateur Radio Direction Finding competitions throughout the country. MRSF supports local competitions in Amateur Radio Direction Finding as well as a national team that travels to regional and world championship events. Although the MRSF has broadened its scope and now supports many kinds of radio activities, the organization's name continues to reflect this early heritage.
The equipment used for direction finding was located on the summit of the hill in a small hexagonal shaped hut. The radio interception equipment was positioned within a control room which was located from the direction finding station. This listening station intercepted VHF radio signals, which were used by German E-boats (fast patrol boats) for short range voice communication. The listening station was part of a chain of stations set up around the country that gathered the enemies raw signals, transmitted in Morse code, for processing at the X-station at Bletchley Park.
A Huff Duff set fitted to HMS Belfast. These sets were common pieces of equipment by the spring of 1943 HMS Kite One of the more important developments was ship-borne direction-finding radio equipment, known as HF/DF (high-frequency direction-finding, or Huff-Duff), which started to be fitted to escorts from February 1942. These sets were common items of equipment by the spring of 1943. HF/DF let an operator determine the direction of a radio signal, regardless of whether the content could be read.
The British and German interception services began to experiment with direction-finding radio equipment in the start of 1915. Captain Round, working for Marconi, had been carrying out experiments for the army in France and Hall instructed him to build a direction-finding system for the navy. At first this was sited at Chelmsford but the location proved a mistake and the equipment was moved to Lowestoft. Other stations were built at Lerwick, Aberdeen, York, Flamborough Head and Birchington and by May 1915 the Admiralty was able to track German submarines crossing the North Sea.
The operation of each company was divided amongst four platoons which were, () which intercepted traffic, () for bearings and fixes on enemy transmitters, Evaluation () and (), which handled all communication problems.I-62, Page 4 The direction finding platoon whose organization was particularly elaborate, operated from tents.I-62, Paragraphs 8-10 Normal direction finding operations for one company called for an average of eight out-stations, spaced 5 to 10 kilometres from each other and parallel to the front of one to several hundred kilometres. From HQ to the outstation was 20-30 kilometers.
Infrasound sensing systems were used for the global monitoring of international compliance with weapon test ban treaties. Military use also involved long-range detection and direction- finding of air or ground vehicles, and detecting and locating artillery fire.
Retrieved Aug. 7, 2008. UARL promotes amateur radio in Ukraine by sponsoring amateur radio operating awards, radio contests, and Amateur Radio Direction Finding competitions. UARL also represents the interests of Ukrainian amateur radio operators before Ukrainian and international telecommunications regulatory authorities.
No. 15 Squadron selected its three best Blenheims – Z7513, Z7610, and T2252 – for the detachment. Each carrying a three-man crew, they arrived at Kufra on 28 April 1942, flying from Amariya via Wadi Halfa to avoid passing over enemy-held territory. Upon arrival, they found that the direction-finding station at Kufra was not functioning properly. Back in Amariya, Lieutenant Colonel Borckenhagen, who had no direct communications with Kufra, asked Royal Air Force Headquarters in the region to pass orders to de Wet on his behalf to keep the detachment grounded until the direction-finding station was made fully operational.
Loop antenna, receiver, and accessories used in amateur radio direction finding at 80 meter wavelength (3.5 MHz). Since the directional response of small loop antennas includes a sharp null in the direction normal to the plane of the loop, they are used in radio direction finding at longer wavelengths. The procedure is to rotate the loop antenna to find the direction where the signal vanishes - the “null” direction. Since the null occurs at two opposite directions along the axis of the loop, other means must be employed to determine which side of the antenna the “nulled” signal is on.
Radio Orienteering in a Compact Area is a variation of Amateur Radio Direction Finding. ROCA is a timed race in which individual competitors use a topographic map and a magnetic compass to navigate through diverse, wooded terrain while searching for radio transmitters.
The area contains the remains of the tower base of, Historic England Grade II listed, Royal Navy World War II direction finding (D/F) station (one of the'Y-stations'), Ventnor, which is believed to be the most complete of its type still extant.
The ship's anti-submarine armament was also gradually increased during the war, with the number of depth charges carried increasing from 15 to as many as 60–90. Other wartime changes included the fitting of radar and High-frequency direction finding gear.
This is a low- level collection team, which typically has four personnel . Their primary equipment is the AN/PRD-13 SOF SIGINT Manpack System (SSMS), with capabilities including direction-finding capability from 2 MHz to 2 GHz, and monitoring from 1 to 1400 MHz.
Werra and were completed in 1922; , and in 1923 and in 1924. Werra had two three-cylinder triple-expansion steam engines and twin screws. Between them her two engines were rated at 604 NHP. Werra was equipped with wireless direction finding and submarine signalling.
Gouin (?). [Hugh Verity, p. 266.] The INVENTOR network was betrayed by double agent Roger Bardet, and on 30 October Vera Leigh was arrested. On 19 November Clech was arrested after his transmissions in Boulogne-Billancourt had been located by the German direction-finding service.
A Navy Direction Finding Station was later erected on the site in 1942. It was manned by U.S. Navy radiomen stationed at Naval Radio Station, Mare Island. The station was closed in 1945 after World War II ended and a Navy Radio Beacon was installed.
Chiefly by means of direction finding it followed the gradual withdrawal of these forces across the Dnieper River. Then, for the first time, it became impossible to solve messages handled by corps and division nets, because the enemy had finally changed all his cryptographic systems.
The new facilities were placed under the direction J. G. Robb. Research under his direction was varied, including a telephone laboratory focusing on audio research, propagation, low noise receivers, radio direction finding and television. A specialist component group developed quartz crystals and gas discharge devices.
The US turned over the base to the Canadian government in 1944 and 1945, which established Naval Radio Station Chimo (call sign CFI) as part of the Canadian Supplementary Radio Activities (SUPRAD) system in 1948. Direction-finding facilities were finished and commenced operations in 1949. In 1950, it became part of the Atlantic high-frequency radio direction finding (HFDF) network after the Royal Canadian Navy and the US Navy agreed to coordinate and standardize their detection operations. The high cost of maintaining and supplying the base, however, led to it being shuttered in late summer 1952 and its equipment and personnel moved to Frobisher Bay on Baffin Island.
This Y Station was a specially constructed wireless interception facility which was also used for direction finding on enemy wireless transmissions. This became particularly important in the Battle of the Atlantic (1939–1945) where locating U-boats became a critical issue. Admiral Dönitz told his commanders that they could not be located if they limited their wireless transmissions to under 30 seconds, but skilled direction finding operators were able to locate the origin of their signals in as little as 6 seconds. There were several of these stations around the east coast, and by triangulating the signals the exact location of enemy shipping could be pinpointed.
However, the introduction of the doppler direction finder, and especially the low-cost electronics to implement it, led to the disappearance of the traditional loop systems by the mid-1990s. Doppler systems use fixed antennae, like BTDF, but handle the direction finding via signal processing alone.
The Enemy Submarine and Direction Finding Section and the code-breakers of Room 40 cooperated to give the convoy planners knowledge U-boat movements. With the advent of coastal convoys, escort composition and technique fell into the hands of the district commanders-in-chief.Abbatiello (2006), 108.
English, p. 111 A Type 271 surface search radar replaced the fire-control director and rangefinder above the bridge. A Type 290 surface warning radar was added at the top of the foremast. A High frequency direction finding system was added on a pole mast aft.
In 1919 he joined the Marconi Company as a theoretical research engineer and stayed there for the remainder of his career. He devoted most of his career to research into radio waves reflected downwards from the Heaviside layer and how they interfered with direction finding equipment.
The Friendship Radiosport Games have traditionally included events from all of the three activities collectively known as radiosport. This includes HF contesting, Amateur Radio Direction Finding, and High Speed Telegraphy. Some competitors participate in only one of these activities, while others have been competitive in multiple events.
Melbourne Star and Brisbane Star each had a pair of 10-cylinder two-stroke single-acting Sulzer Bros marine Diesel engines driving twin screws. Brisbane Stars engines developed a total of 2,806 HP. Her navigation equipment included wireless direction finding, an echo sounding device and a gyrocompass.
It was concluded, however, that Allied direction finding was the source. The Germans also recovered a cavity magnetron from a downed British bomber. The conclusion was that the Enigma was secure. The Germans were still suspicious, so each submarine got its own key net in June 1944.
The lifeboat was fitted with Decca 060 radar and all she carried Pye Westminster VHF and an Ajax MF radio telephones. In addition a radio Direction Finding set was carried, which gave a magnetic bearing to a transmitting station. The electric searchlight was standard along with Pains Wessex speedlines.
The lifeboat was fitted with Decca 060 radar and all she carried Pye Westminster VHF and an Ajax MF Radiotelephone. In addition a radio Direction Finding set was carried, which gave a magnetic bearing to a transmitting station. The electric searchlight was standard along with Pains Wessex speedlines.
The IARU rules include detailed technical specifications for transmitter equipment.IARU Region I ARDF Working Group (2010) "Rules for Championships in Amateur Radio Direction Finding Part B: Competition". Retrieved March 27, 2011. Transmitters for two meters are typically 0.25 to 1 watts power output, and use keyed amplitude modulation.
Her bridge was remodelled to improve visibility and a pair of echo sounders were fitted in addition to a navigational radar and direction-finding gear. The changes increased her displacement to at standard and at deep load. Her crew now consisted of 82 officers and ratings.du Toit, pp.
The USMC 1st Composite Radio Company deployed, on January 2, 1962, to Pleiku, South Vietnam as Detachment One. After Davis' death in December, it became obvious to the Army Security Agency that thick jungle made tactical ground collection exceptionally dangerous, and direction-finding moved principally to aircraft platforms.
Kenneth Morton Evans was appointed Deputy Controller. Roland Keen, author of "Wireless Direction Finding", was the officer in charge of engineering. The service was well-financed. It was equipped with a new central radio station at Hanslope Park in Buckinghamshire (designated Special Communications Unit No.3 or SCU3).
Royal Air Force Danby Beacon or more simply RAF Danby Beacon was an early warning radar Royal Air Force station that formed part of the Chain Home network of radar (or Radio Direction Finding (RDF)) stations built by the Royal Air Force immediately prior to the Second World War.
Errors in interpretation also occurred. However, such instances were rare, since all unconfirmed reports were given With reservations. For example, prior to the invasion of Sicily, a British message spoke of a successful landing. Since only one direction- finding team was available, only one bearing could be taken.
Boat with direction finding birds to find land. Model of Mohenjo-Daro seal, 2500-1750 BCE. Numerous objects found in excavation include seated and standing figures, copper and stone tools, carved seals, balance-scales and weights, gold and jasper jewellery, and children's toys.Mohenjo-daro Tools and Artifacts Photo Gallery.
Its post office dates from 1857. During World War II, the Royal Canadian Navy set up an radio direction finding (radar) station at Lambeth. Its purpose was to acquire a bearing whenever a German U-boat transmitted a radio messages back to their HQ. The resultant bearing was then sent to the Officer-In-Charge in Ottawa over a dedicated teletype line. Direction finding equipment was housed in a white shack located at an airfield in what is now a big box retail complex at the northwest corner of Wharncliffe Road and Wonderland Road (formerly Airport Road) a couple of kilometres from Lambeth. The station began operating in the first few days of January 1943 and closed war’s end.
USAFSS support to national customers expanded in the late 1950s and early 1960s. USAFSS ground units opened in out of the way places around the globe, including Diyarbakir, Samsun and Trabzon Air Force Detachments in Turkey, Iraklion Air Station, Crete, Zweibrucken and Wiesbaden Air Bases in Germany, Royal Air Force Kirknewton in Scotland, and Peshawar, Pakistan. In the 1970s, major installations included Misawa AB, Japan, San Vito Air Station, Italy and RAF Chicksands, England. Locations like Elmendorf AFB and Clark AB were equipped with direction finding shops from which "fixes" on targets could be obtained by requesting a line of bearing from other direction finding shops in other locations around the world.
1953 Page: 3 The Manxmans main duties were at Cherbourg, but she was also deeply involved at the small port of St Malo, to the east, where she was the last ship to leave the shattered harbour. In October 1941, she was fitted out as an RDF – Radio Direction Finding Vessel – and having been taken over for the second time by the Admiralty, she was commissioned as HMS Caduceus. She was then ordered to her former home port of Douglas, where on Douglas Head there was situated one of the early radar training stations - . From Douglas she spent some time on patrol in the Irish Sea, while naval personnel were initiated into the workings of radio direction finding.
A portable, battery operated GT-302 Accumatic automatic direction finder for marine use Radio direction finding, radio direction finder, or RDF, was once the primary aviation navigational aid. (Range and Direction Finding was the abbreviation used to describe the predecessor to radar.) Beacons were used to mark "airways" intersections and to define departure and approach procedures. Since the signal transmitted contains no information about bearing or distance, these beacons are referred to as non-directional beacons, or NDB in the aviation world. Starting in the 1950s, these beacons were generally replaced by the VOR system, in which the bearing to the navigational aid is measured from the signal itself; therefore no specialized antenna with moving parts is required.
In January 1961, while the Vietnam embassy and military group prepared a counterinsurgency plan, the SIGINT community did its own planning. The first review of the situation assumed limited support to the ARVN COMINT teams. Essentially, the policy was that the South Vietnamese would be trained in basic direction finding using "known or derived" technical information, but, for security reasons, COMINT that involved more sophisticated analysis would not be shared. It was also felt that for at least the near term, ARVN COMINT could not provide meaningful support, and the question was presented, to the State Department, if it was politically feasible to have US direction-finding teams operate inside South Vietnam.
The Navy also claimed over the years that the direction finding sites were used primarily for air and sea rescue operations and Naval communications in the case of the pair of FRD-10s at Sugar Grove Station. The FRD-10 used a goniometer to rapidly scan through all the antennas around the circle. This electronically "rotated" the antenna 360 degrees several times a second allowing fast and accurate direction finding. This was needed because Soviet submarines began to use wide-band burst transmissions in the early 1960s to make themselves more difficult to pinpoint. Initially, these signals were too rapid for Bullseye's predecessor, Boresight, to locate, but the AN/FRD-10 was able to locate even very brief transmissions.
CASARA may be tasked at any time of day or night and can conduct both electronic direction-finding missions and visual searches. They are a primary source of trained spotters for military and civilian aircraft participating in major searches, and they often provide or arrange facilities for temporary search headquarters.
ARDF equipment is a specialty market, and much of what is available for purchase comes from small commercial vendors or small-batch production by individuals. Building equipment, such as handheld antennas, from published designs or kits is also a popular activity.Hunt, Dale WB6BYU (2005). "A Simple Direction-Finding Receiver for 80 Meters". QST.
The ASA unit at Rothwesten was a main intercept and MARBURG-equipped special identification techniques (SIT) site during the Cold War. It was also a mainstay of the European direction finding (DF) network. Also on the Kaserne was a battery of Hawk Air Defense Missiles. This was "Charlie" Btry, 6th BN, 517th Arty.
Naval Security Group detachment Diego Garcia was disestablished on 30 September 2005.OPNAVNOTE 5450 dated 6 September 2005. Remaining essential operations were transferred to a contractor. The large AN/AX-16 High Frequency Radio direction finding Circularly Disposed Antenna Array has been demolished, but the four satellite antenna radomes around the site remain .
Bodiansky, p. 139-140 In January 1951, the squadron moved to Misawa Air Base, Japan, where one of the first Elephant Cage high frequency direction finding antenna assemblies was located.Bodiansky, p. 160-161 The squadron was inactivated in May 1955, and its mission, personnel and equipment transferred to the 6921st Radio Squadron, Mobile.
During World War II his inventions were instrumental in radio direction finding, including four secret patents relating to the automatic high-frequency direction finding (Huff-Duff) system used to locate German U-boats. Busignies had escaped from German-occupied Paris with his wife and working models, ultimately making his way to the United States, where the inventions were implemented first along the East Coast, then the West Coast, with another 30 to 40 fixed stations located around the world. About 1,000 smaller systems were installed on aircraft carriers and destroyers, as well as a further 1,500 mobile systems for the Army Signal Corps. He was also closely involved in early development of Moving Target Indication (MTI) radar during the war.
Each system operates on 145 ground mobile vehicles which has three communication and two non-communication segments and can cover an area of 150 km by 70 km. System has the capability for surveillance, analysis, interception, direction finding, and position fixing, listing, prioritising and jamming of all communication and radar signals from HF to MMW.
All 5 crew members were declared KIA Bodies Not Recovered. Two later re-converted to U-21A standard. ;RU-21A :Conversion of four U-21As to carry Direction finding equipment as part of Cefirm Leader program, to work with RU-21B and RU-21C aircraft.Kaminsky International Air Power Review Winter 2003/2004, pp. 89–90.
The Chinese Radio Sports Association was founded on April 3, 1964. The organization initially focused on radiosport activities, specifically High Speed Telegraphy and Amateur Radio Direction Finding. It is the national member society representing the People's Republic of China in the International Amateur Radio Union, which it joined in 1984.International Amateur Radio Union (2008).
German submarines use multiple SIGINT systems. The newer Type 212 submarines use FL 1800U units made by the German-French EADS consortium. These units use four spiral antennas and a radar warning receiver under a common dome, with the ELINT function covering 0.5–18 GHz in five bands. This can achieve 5-degree direction finding.
The flight resumed three days later from Luke Field with Earhart, Noonan and Manning on board. The next destination was Howland Island, a small island in the Pacific. Manning, the only skilled radio operator, had made arrangements to use radio direction finding to home in to the island. The flight never left Luke Field.
Freud, S. The Psychopathology of Everyday Life, chapter 1, "Forgetting of Proper Names". Freud denies the relevance of the content of the frescos. Nevertheless, psychoanalysts have pursued their investigations particularly into this direction, finding however no new explanation of the parapraxis. Jacques Lacan suggested that the parapraxis may be an act of self-forgetting.
However, the computation of the inverse of f is generally hard, unless the trapdoor t is given.Ostrovsky, pp. 6-9 A trapdoor function is a function that is easy to compute in one direction, yet difficult to compute in the opposite direction (finding its inverse) without special information, called the "trapdoor". Trapdoor functions are widely used in cryptography.
One antenna can receive over a wide bandwidth, for example a ratio 5:1 between the maximum and minimum frequency. Usually a pair of spiral antennas are used in this application, having identical parameters except the polarization, which is opposite (one is right-hand, the other left- hand oriented). Spiral antennas are useful for microwave direction-finding.
In 1964, the USAFSS began using the C-47 Airborne Direction Finding platform, providing intelligence to U.S. and friendly commanders throughout Southeast Asia. From 1964 to 1971, Kadena AB was the home-base for long-range surveillance flights over China, DRPK, and North Vietnam by unmanned aerial vehicles (UAVs) or ‘drones’ produced by Ryan Aeronautical Company.
"Fox-Oring: Just Like Orienteering with Hidden Controls!!!". Retrieved December 2, 2005. Another variation of the sport, Radio Orienteering in a Compact Area, requires less athletic skill and more technical radio direction finding skills. In a ROCA course, the transmitters put out very little power, typically 10 to 200 mW, and can be received over only very short distances.
The rules used throughout the world, with minor variations, are maintained by the IARU Region I ARDF Working Group.IARU Region I ARDF Working Group. "Rules for Championships in Amateur Radio Direction Finding". Although these rules were developed specifically for international competitions, they have become the de facto standard used as the basis for all international competitions worldwide.
The Alaskan Command was reestablished at Elmendorf in 1989 as subunified joint service command under the Pacific Command in recognition of Alaska's military importance in the Pacific region. The Elmendorf AFB is a site of one of the now decommissioned FLR-9 Wullenweber- class antennas, a node of the now obsolete High Frequency SIGINT direction finding system.
Major improvements are an improved direction- finding antenna and an EP-2060 pulse analyzer. The dedicated SIGINT EP-3 uses a JMOD (Joint Airborne SIGINT Modification) program to a JMOD common configuration (JCC). Northrop Grumman developed the SIGINT package for the Global Hawk UAV. An upgraded version of the same SIGINT payload is flown on U-2.
The paper describes the device in depth, and goes on to explain how it could be used to improve radio direction finding and navigation. In spite of this public demonstration, and films showing it being used to locate lightning, the concept apparently remained unknown outside the UK. This allowed it to be developed into practical form in secret.
In: Heinemann, 2011 p.34/35 Around 4000 people were involved in radio intelligence during the period of world war 2. The stations themselves were in remote coastal locations for maximum security and freedom from interference by other electro-magnetic sources. For successful direction finding, a minimum intercept angle of 15° between two bearing bases was necessary.
Duchess of Atholl carried wireless direction finding equipment and submarine signalling equipment. Submarine signalling was becoming obsolete as a form of communication, so by 1937 it had been removed and echo sounding equipment had been installed. Duchess of Atholls net register tonnage was slightly revised several times in the 1930s. From 1939 it was listed as .
The German V-1 Buzz Bomb also used an autopilot system for guidance. It used a pendulum system that was damped by a gyroscope, similar to the ones used in Sperry autopilots. It also used radio direction finding to maintain course. The use of autopilot on unmanned weapons can be seen as the precursor to modern cruise missiles.
Before 1974 when the AN/FPS-35 was replaced, FCC direction- finding equipment was used after the radar "scopes would light up like light bulbs" almost every morning for a half-hour—a noisy UHF TV tuner in the area was located which was being used for a "soap opera on one of the local channels".
Bogomolov was the Chief Designer (Director) of MPEI Special Design Bureau from 1954 to 1989. He also was a member of Sergey Korolev's Council of Chief Designers. He did research at the fields of radiotelemetry, trajectory measurements, phase direction finding and antenna systems. He took part in testing of R-16 in 1960 at Baikonur and survived Nedelin catastrophe.
These fed steam at 215 lbf/in2 to two four-cylinder quadruple expansion steam engines, developing a total of 984 NHP. Each engine drove one of the ship's twin screws, giving Rohna 984 NHP or 5,000 ihp. She achieved on her sea trials and had a cruising speed of . By 1934, Rohna carried wireless direction finding equipment.
On 19 November Clech was arrested in Boulogne-Billancourt after his transmissions was located by the German direction-finding service, and Jones was arrested the next day. Leigh was executed at Natzweiler-Struthof concentration camp, Clech was executed at Mauthausen concentration camp on 24 March 1944. Jones was executed at Mauthausen on 16 September 1944, aged 42.
In accordance with policy, it was shut down to deny the Germans the opportunity to use it as direction-finding beacon and the BBC Home Service was kicked off air in the process. Using the railway lines, Roth, in the lead Do 17, homed in on Kenley from the south. They were now just six miles away.
Later, communications progressed to visual and audible signals, and then advanced into the electronic age. Examples from Jane's Military Communications include text, audio, facsimile, tactical ground-based communications, naval signalling, terrestrial microwave, tropospheric scatter, satellite communications systems and equipment, surveillance and signal analysis, encryption and security and direction-finding and jamming.IHS Jane's Military Communications. Retrieved 2012-01-23.
"Radio Mechanic" was a termed used in 1940 to describe "radar technician". In 1940 the term "radar" had not been coined and the British referred to radar as "Radio Direction Finding". Radar technology was a secret, strategic part of the air war. Thousands of technicians were required to install and maintain radar sets in aircraft and ground stations.
During World War II, Hemingway used his boat to search for German U-boats in the Caribbean waters. Pilar was outfitted with communications gear including HF/DF or “Huff-Duff” direction-finding equipment. His minimal armament included a Thompson sub machine gun and hand grenades. Most accounts state that any effort to attack a submarine would be futile.
Centerboard was a network for processing HF/DF information. The security classification guide that covered all three programs was cancelled in January 2009. Later, the programs Unitary DF and Crosshair sought to unify the military's HF direction finding information into a single data collection network. Crosshair, an HF/DF geolocation network, is apparently still in use c.
Sites in the Classic Bullseye network were connected by communications links to facilitate "near instantaneous" triangulation of received signals if two or more sites received the same signal. Signals could also be recorded for later direction finding. The system was four times more accurate than the prior Navy AN/GRD-6 system with bearing accuracy better than 0.5 degrees.
The Government Code and Cypher School (GC&CS;) code-breaking organisation at Bletchley Park read German radio signals encrypted by the Enigma cypher machine and was part of an elaborate system of wireless listening posts, traffic analysis and direction finding used against Germany during the war. Ultra decrypts on 11 and 18 March 1944 established the existence of and that its headquarters was in Paris. A big increase in wireless traffic from was detected by the British Monitoring Section on 8 June 1944, when the 17th SS Panzergrenadier Division came under the command of the . The site of the source was identified by High-frequency direction finding ("huff-duff") at the château in the commune of La Caine, about to the south-west of the city of Caen.
By rotating a small loop antenna, the sense coil, in the space between the two crossed field coils, one could perform DF. In effect, it recreated the traditional technique at a much smaller scale, allowing the main antennas to be built at any size. Robert Watson-Watt introduced the next major advance in direction finding as the "huff-duff" system, a nickname for high-frequency direction finding. Huff-duff also used crossed antennas, often an Adcock antenna, but sent their output to the two channels of an oscilloscope. The relative strengths and phases of the two signals deflected the X and Y locations of the oscilloscope's electron beam by different amounts, causing an ellipse or figure-8 to appear on the screen, with the long axis indicating the direction of the signal.
Maxwell K. Goldstein (January 15, 1908 – February 18, 1980) was a first generation Jewish-American scientist and engineer who was instrumental in the development and deployment of high-frequency direction finding by the United States Navy during the Second World War. High-frequency direction finding (known as huff-duff or HF/DF) played a significant role in the Allies efforts to counter the threat of German U-boats (submarines) during the Battle of the Atlantic. This success helped ensure the continued flow of equipment and supplies from the United States to Britain and to European battlefields, which was a critical factor in the ultimate Allied victory. Following World War II, Goldstein founded Balco Research Laboratory, which specialized in high resistance capacitors used in numerous military, civilian, and NASA projects.
A typical use of Butler matrices is in the base stations of mobile networks to keep the beams pointing towards the mobile users.Balanis & Ioannides, pp. 39-40 Linear antenna arrays driven by Butler matrices, or some other beam-forming network, to produce a scanning beam are used in direction finding applications. They are important for military warning systems and target location.
Koninklijke Maatschappij De Schelde built Slamat in Vlissingen on the River Scheldt, completing her in 1924. Her boilers had oil- burning furnaces, and her engines were steam turbines that drove her twin screws via double reduction gearing. She was equipped with submarine signalling apparatus, which in the 1920s was seen as an alternative to radio. She also had wireless direction finding equipment.
A HACS Mk III director replaced the Mk I in the spotting top and another replaced the torpedo director aft. A pair of quadruple mounts for Vickers .50 machine guns were added abreast the conning tower. The mainmast was reconstructed as a tripod to support the weight of a radio-direction finding office and a second High-Angle Control Station.
The infrasonic sensing array, designed by the U.S. Army Research Laboratory (ARL), was a military device that detected and located explosive events with inaudible frequencies at long ranges, such as artillery, missiles, and helicopters through the use of the array process. It was also used for direction-finding and positioning for navigational purposes and for detecting atmospheric events for battlefield weather prediction.
Struszynski was born in Moscow in 1904, and the family moved to Warsaw in 1916. He received his Masters in Engineering (Dipl. Ing.) at the Warsaw University of Technology in 1928, and joined the Polish State Telecommunication Establishment, where he became head of the Direction Finding Division. When Poland was invaded in 1939, he was evacuated from Warsaw, and reached England in 1940.
After 1993, the organization opened its membership to individual amateur radio operators and was given the responsibility of administering the amateur radio license certification program for the country.. The CRSA was the host organization for the 2000 World Amateur Radio Direction Finding Championships, which were held October 13–18 in Nanjing.Deutscher Amateur-Radio-Club (2009). "ARDF- Worldchampionship Okt. 2000 Nanjing/China".
In the cave, Mary takes to playing music on her car's console radio. Under cover of this, she uses the pack radio stolen from Haines to call for help. Her call interferes with the broadcast of the Kentucky Derby, and is overheard by Haines in a bar. When she calls again, Federal agents locate her approximate position by radio direction finding.
In November 1940 she sailed back to Kiel, then to Rotterdam to get armaments fitted. These consisted of three French 75mm guns and three German 20mm guns. The Esso Hamburg was also fitted with a Direction finding (DF) device. In late December 1940, she sailed for Cherbourg where her gun platforms were strengthened and additional fresh water tanks were added.
These regional officers are elected by representatives from the member societies at triennial regional conferences. Coordinators may be appointed by the Executive Committee of their region to support particular areas within the region, or to promote certain amateur radio activities within the region. All three regions have appointed Coordinators for Amateur Radio Direction Finding, emergency communications, monitoring for electromagnetic interference, and radio propagation.
The IARU organises and promotes radiosport activities throughout the world. The IARU promulgates the rules used for high-speed telegraphy and sponsors regional and world championships. The IARU also promulgates the rules used by most competitions in amateur radio direction finding, including IARU-sponsored regional and world championships. The IARU also sponsors the annual IARU HF World Championship in amateur radio contesting.
The lifeboats onboard equipment includes the latest in electronic equipment including radar, a chart plotter and VHF radio direction finding equipment. Running around the outside of the hull is an inflatable tube constructed of tough Nylon weave. This tube, or sponson is made up of separate compartments. If one of the compartments is accidentally punctured then the others will remain inflated.
To further simplify the system, it is possible to simulate the movement of the antenna with a small amount of additional electronics. This is the pseudo-Doppler direction finding technique. Consider a pair of omnidirectional antennas receiving a signal from a target transmitter. As the signal propagates past the receiver, the amplitude of the signal at the antennas rises and falls.
It was not until April 1945 that AWS-4 departed Los Negros bound for the Southern Philippines. The squadron landed on Mindanao and quickly established itself at Moret Field operating as the 76th Fighter Control Center. AWS-4 was tasked with providing direction finding for lost aircraft, early warning, additional air to ground communications links and additional fighter direction nets.
The destroyer picked up the transmission, and used High-frequency direction finding (HF/DF) to direct an attack against the German submarine by Leamington, , and . They attacked and sunk U-587 with depth charges, the first submarine sunk with the aid of shipboard HF/DF.Blair Hitler's U Boat War: The Hunters 1939–42 2000, p. 513.Rohwer and Hümmelchen 1992, p. 132.
Her tonnages were ; 6,571 tonnage under deck; and 10,821 DWT. She was fitted with direction finding equipment. She had nine corrugated furnaces with a combined grate surface of that heated three single-ended boilers with a combined heating surface of . The boilers fed a three-cylinder triple-expansion steam engine rated at 506 NHP or , with cylinders of , and diameter by stroke.
During World War II, Rivers became one of the sites in Canada which helped to fix the positions of German U-boats using High Frequency Direction Finding. This site, along with Portage la Prairie increased the "fix" accuracy on the U-boats. CFB Rivers, a former military base, is located four miles west of the community. It was decommissioned in 1971.
The use of radio codes increased by both the service and the smugglers so the Coast Guard had to develop cryptanalysis skills to keep ahead of the smugglers."Cryptology, Elizebeth Friedman and the United States Coast Guard Thwart the Rumrunners". Cryptologic Heritage: Publications, National Security Agency Radio direction finding equipment was installed on several Coast Guard vessels in late 1930.
There are also signs of a Fletton brick wall running westward away from the raised area. The octagonal shape of the base indicates that a direction-finding station operator's hut stood there. It would have consisted of a double-skinned wooden structure in which the cavity was filled with shingle pebbles designed to make the structure "splinter proof" or "bulletproof".
The Civil Air Patrol performs emergency services missions, including search and rescue (SAR) missions directed by the Air Force Rescue Coordination Center. Aircrews can perform visual and electronic searches, while ground teams home in on the search target with direction finding equipment. After a disaster, Civil Air Patrol personnel provide humanitarian support, including air/ground transportation, as well as an extensive communications network.
75–9 The investigators found this striking (German:Besonders Auffällig), as according to Dönitz reports, the U-boats in the southern sector had not signaled their position after departure, and Kriegsmarine Command had not received any information regarding their attacks since heading south. The Admiralty intercepts had added no cross bearing and no direction finding, so Huff-Duff direction finding did not appear to be the source of the information leading to the location of the submarine pack. However, the investigation team had discovered that another U-Boat, had signaled, and the Admiralty needed to see it, it must have been noticed and have been included in the Admiralty Situation Report. The report concluded it is unambiguously clear that that U-boat would have been announced with the one which signaled at 1209 on 2nd September (U-83).
Gun emplacements belonging to the coastal artillery school. The Royal Artillery coast artillery school was transferred from Shoeburyness to the Great Orme in 1940 (and additionally a Practice Camp was established on the Little Orme in 1941) during the Second World War. Target practice was undertaken from the headland to both towed and anchored boats. Experimental work and training was also provided for radio direction finding.
The Freya controllers could now see which blips on their screens were enemy and friendly. None of the devices had been tested in combat. Luftwaffe controllers opted to use radio transmissions (Y-service) at the time instead, since it was proven in bomber navigation. Through using transmitters, receivers and direction finding equipment, the bearing, height and range of the night fighter could be determined.
That left only the Arctic convoys to the Soviet Union. On Christmas Eve, this became the sole preserve of the U-boats after the dispatch of Scharnhorst at the Battle of the North Cape. Dönitz's plan for 1944 was simply to survive and await the XXI and Type XXIII submarine. New radars were on the horizon and a direction finding antenna for Naxos was scheduled for use.
The transmitters are physically small, and marked with a control card that is no larger than a typical postcard with a unique number identification. Because of the low power and short distances involved, most ROCA competitors walk the entire course, and focus their attention on the radio direction finding tasks rather than navigation.Crystal, Bonnie KQ6XA (1998). "Radio-Orienteering in a Compact Area: The New Walking Foxhunt".
106 Ark Royal's aircraft attacked Italian land bases for the first time in August 1940. British bombing of airbases and mine laying at Cagliari harbor were unsuccessfully opposed by the Italian air force.Whitehouse p. 62-64 On the last day of August, a significant British technological development, radio direction finding (RDF) aka radar, was first used to alert the Ark Royal to approaching enemy aircraft.
For fire control, Sposobny received the Yatagan guidance radar for her Volna, the Turel for her AK-726, and the Groza for her torpedoes. Sposobny also had a MG-26 communications outfit, a Triton transceiver, the MPP-315 remote indicator for her Volga, and the Nikel-KM identification friend or foe system. For electronic warfare she was equipped with the MRP 13–14 direction finding system.
Undaunted was fitted with a Type 291 air warning and Type 276 surface warning radar on the ship's lattice foremast, together with a high- frequency direction finding (HF/DF) aerial. A Type 285 fire control radar integrated with the ship's high-angle gun director, while the Hazemayer mount had an integrated Type 282 radar. Undaunted had a crew of 179 officers and other ranks.
Formally established on 1 September 1977, the GCSB was located within the Ministry of Defence for reasons of cover. "The fact of" GCSB was disclosed, in 1980, to the Cabinet and Opposition Leader, but with SIGINT functions excluded. Only in 1984 was the SIGINT function of GCSB announced by the Prime Minister. In 1982, the HF radio interception and Direction finding station at Tangimoana was opened.
Direction finding requires an antenna that is directional (more sensitive in certain directions than in others). Many antenna designs exhibit this property. For example, a Yagi antenna has quite pronounced directionality, so the source of a transmission can be determined simply by pointing it in the direction where the maximum signal level is obtained. However, to establish direction to great accuracy requires more sophisticated technique.
D&W; Henderson & Co of Glasgow built Cyclops in 1906 for Ocean Steam Ship Co, Alfred Holt's ship-owning company. She had twin screws, each powered by its own three-cylinder triple-expansion steam engine. Between them the two engines developed 585 nhp and gave the ship a speed of . Cyclops had been equipped with wireless by 1930 and wireless direction finding by 1933.
The shorter antennules provide a further sense of smell. By having a pair of olfactory organs, a lobster can locate the direction a smell comes from, much the same way humans can hear the direction a sound comes from. In addition to sensing smells, the antennules can judge water speed to improve direction finding. Lobsters have two urinary bladders, located on either side of the head.
Reaching that number gave them exemption from other duties, such as fire watching. Also, many VIs were issued a special DR12 identity card. This allowed them to enter premises which they suspected to be the transmission source of unauthorized signals. RSS also established a series of Radio Direction Finding stations, in the far corners of the British Isles, to identify the locations of the intercepted transmissions.
This freedom gave them much greater tactical flexibility, allowing the support groups to detach ships to hunt submarines spotted by reconnaissance or picked up by high-frequency direction finding (HF/DF). In situations where the regular escorts would have had to return to their convoy, the support groups were able to persist in hunting a submarine for many hours until it was forced to the surface.
TRSSCOMM had the advantage of being able to transmit large quantities of intelligence information very rapidly without giving away the ship's location to hostile direction-finding equipment or interfering with incoming signals. Its major disadvantage is that it could only work if the moon was visible and the shipboard hydraulic stabilization system worked properly. This system was replaced by creation of a network of artificial military satellites.
In a growing age of passenger ships having cruiser sterns, Morro Castle and Oriente were built with classic counter sterns. As built, Morro Castle was equipped with direction finding equipment and submarine signalling equipment. Submarine signalling was becoming obsolete as a form of communication, so by 1934 it had been removed. Also by 1934 echo sounding equipment and a gyrocompass had been installed on the ship.
These patrols surveyed major centers of enemy activity. The patrols reconnoitered Argentinian positions at night, and then due to the lack of cover moved to distant observation posts (OPs). Information gathered was relayed to the fleet by secure radio not impervious from SIGINT that could locate their OPs. No common understanding of the threat of Argentine direction finding existed, and different teams developed individual solutions.
While a research scholar at University of Melbourne, Boswell worked in a team of four using radio direction-finding to trace the movement of thunderstorms associated with cold fronts crossing the southern part of Australia, and for his work was awarded a Fred Knight scholarship. Boswell was made an Officer of the Order of the British Empire in May 1956 for his role in guided weapons development.
The mission was a success. To prevent their camp being located or compromised by German radio direction finding equipment or informers, Tonkin regularly moved its location. The location of new camps had to be close to water and a drop zone for parachute supply. The camp located near to Verrières was near to their drop zone at La Font d'Usson and had an adequate water supply.
Direction-finding checks also enabled the controller to keep the pilot on course. The crew would be ordered to drop their bombs either by a code word from the ground controller or at the conclusion of the signal transmissions which would stop. The maximum range of Y-Gerät was similar to the other systems and it was accurate enough on occasion for specific buildings to be hit.
The SCR-658 radar is a radio direction finding set introduced by the U. S. Army in 1944, was developed in conjunction with the SCR-268 radar. It was preceded by the SCR-258. Its primary purpose was to track weather balloons. Prior to this it was only possible to track weather balloons with a theodolite, causing difficulty with visual tracking in poor weather conditions.
No.53 Radio Direction Finding Station was established in 1943 at Mount Surprise as one of 25 RDF stations controlled by the Royal Australian Air Force No.42 Radar Wing Headquarters in Townsville. These stations were constructed across northern Australia to provide warning of potential Japanese aircraft raids on Queensland's eastern seaboard centres. They utilised the most secretive of new technology and for security reasons little was known by the wider community of their existence and function. Frequently much of the associated infrastructure at these sites was removed or demolished after World War II. In response to the Japanese military dominance in Southeast Asia and the western Pacific in 1942-43 and with the invasion of Australia seemingly imminent, a network of Radio Direction Finding (RDF) stations was established throughout the northern inland and coastal regions of Australia and Papua New Guinea and islands of the western Pacific Ocean.
Messages were intercepted here and bearings on enemy transmissions were provided using direction finding techniques. The station closed in 1946; however, the building that housed the station still stands in a remote corner of the University of Victoria, having been moved from its original location. Today, many homes in Gordon Head have secondary suites in order to both improve housing affordability and meet the housing demands of the local student population.
CODAR Ocean Sensors (COS) The latest generation of shore-based ocean radar can reach more than 200 km for ocean current mapping and more than 100 km for wave measurements Helzel WERA. For all ocean radars, the accuracy in range is excellent. With shorter ranges, the range resolution gets finer. The angular resolution and accuracy depends on the used antenna array configuration and applied algorithms (direction finding or beam forming).
Competitors start at staggered intervals, are individually timed, and are expected to perform all radio direction finding and navigation skills on their own. Standings are determined first by the number of transmitters found, then by shortest time on course. Competitors who take longer than the specified time limit to finish may be disqualified. ARDF events use radio frequencies on either the 2-meter or 80-meter amateur radio bands.
The engines gave Patria a total of 900 NHP and propelled the ship by twin screws. Patria had direction finding equipment and was the first ocean liner to be equipped with a cinema. Patria was launched on 11 November 1913 and entered Fabre Line service on 15 or 16 April 1914. The New York Times reported that a German submarine attacked her on 1 March 1916 off the coast of Tunis.
The next day she also sank another British ship, the 3,701 ton Radchurch, which had been abandoned. The convoy escort was then reinforced by the Polish destroyer and the British destroyer leader . Both ships were equipped with HF/DF (radio direction-finding equipment), which helped to keep the U-boats at bay until morning. U-176 sank the 7,457 ton British cargo ship with two torpedoes on 25 August.
From Ascension Island the ocean boarding vessel HMS Corinthian, a converted Ellerman Lines cargo steamship, put to sea to find the survivors. Corinthian had direction finding equipment with which it tracked the survivors' wireless signals. At 1030 hrs on 11 October she sighted the lifeboats, and within five hours she had rescued all 821 survivors. The Free French escorted Corinthian to Freetown, where they arrived on 15 October.
In 1996, Japan created its first post- WWII major intelligence organization, the Defense Intelligence Headquarters (DIH). Its SIGINT Division is the largest in the organization, with a Ground Self Defense Force unit in Ichigawa, targeting North Korea. The Division also has two Wullenweber intercept and direction finding, as well as offices in Kobunato (in Niigata Prefecture), Oi (in Saitama Prefecture), Tachiarai (in Fukushima Prefecture), and Kikaijima (in Kagoshima Prefecture).
Cammell Laird of Birkenhead, England, built Abosso for Elder Dempster Lines in 1935. She was launched on 19 June, completed on 8 September and began her maiden voyage on 16 October. Abosso was a motor ship, with two eight-cylinder two-stroke single-acting marine diesel engines driving twin screws and a combined rating of 1,660 NHP. Her navigation equipment included wireless direction finding and an echo sounding device.
Eventually, an ASA contingent was put together from resources in the Philippines. Thailand imposed a limit of fifty SIGINT personnel for the site, which eliminated the possibility of adequate direction finding. The compromise was to intercept at the site, but to send the raw data to the Philippines for processing. Thai sensitivities were such that a permanent site was not selected until 1965, when the Udon base was established.
CEFIRM LEADER, first known as CRAZY DOG, was an attempt to build a system, called V-SCANARDF, the combined intercept, direction finding, and jamming for the 2-80 MHz frequency range. Implementation involved one of the features to appear in the much later Guardrail series, using several aircraft in a team. RU-21A's carried AN/ARD-22 direction finders. RU-21B's were COMINT intercept aircraft with the AN/ALT-32.
The escort carrier had been hunting weather boats for nearly a month and had already sunk and . Intercepted radio transmissions led Croatan and six destroyers to search for U-853. The U-853 proved so elusive that Croatan's crew nicknamed their prey "Moby Dick." After ten days of hunting, on 17 June Huff-Duff (HF/DF, high frequency direction finding) picked up a weather report from U-853 only away.
Amateur Radio, Volume 59, Issues 1-6 "Steve Bowden, ZC4BX, recently returned to the UK after three years on Cyprus, where he initiated and managed the ZC4 award." There are about 52 amateurs licensed in this manner. Amateur radio direction finding identified RAF Akrotiri as the location of the powerful but now defunct shortwave numbers station "Lincolnshire Poacher". Several curtain antennas there have been identified as being used for these transmissions.
Later the newspaper's mission was changed to become one that is independent and free from any political factions. The publication was initially named Bentara Rakyat (People's Herald). At President Sukarno's suggestion, it was renamed to Kompas, for the direction-finding instrument. Kompas began publication on 28 June 1965 from an office in central Jakarta. Its circulation grew from initial circulation of 4,800 copies in 1965 to around 500,000 in 2014.
On 1 April 1944 he narrowly escaped another capture by the Gestapo when one of his transmitters, hidden in the Oslo Maternity Hospital, was located by radio direction finding. Haugland fled to the United Kingdom again, and did not return. He was awarded Norway's highest decoration for military gallantry, the War Cross with sword. He was awarded this decoration twice, in 1943 and 1944: the War Cross with two swords.
Even if the British had captured the materials intact and could read Enigma, the British would lose that ability when the keys changed on 1 November. Although Germany realized that convoys were avoiding its wolfpacks, it did not attribute that ability to reading Enigma traffic. Instead, Dönitz thought that Britain was using radar and direction finding. The Kriegsmarine continued to increase the number of networks to avoid superimposition attacks on Enigma.
To these were added a small cryptanalysis group, that was called the Chi-Stelle which served all three sections.IF-180, p. 2 The intercept stations were supplemented by direction finding stations which were called Weather Research Stations () (abbr. Wo-Stellen), after the start of World War II. The small sections were expanded into mobile Radio Intercept Companies () which collaborated with the fixed stations in the intercept of foreign air force traffic.
Special design considerations include adequate strength to withstand the wind at highway vehicle speeds and ease of repair after collisions with overhead tree branches. In mobile transmitter hunts, directional antennas are often turned by hand while the vehicle is in motion. Some radio direction finding equipment popular with mobile transmitter hunters operates on the time difference of arrival principal. Two identical antennas are mounted a precise distance apart from one another.
Rather than plotting locations, (dead reckoning) Irish Willow was using direction finding equipment; she was travelling towards the SOS signal: It was dangerous for Irish Willow. They knew the direction to take, but did not know the distance. Travelling in fog, they could collide with Empire Breeze, or endanger survivors in the water. Extra look-outs were posted along her bow and whistles were sounded every two minutes.
Newman maintained tight security, transmitting from three separate locations and never transmitting more than twice from the same location before moving to the next, but German direction-finding teams were close to arresting him and he was forced to cease transmission for six weeks at one point. On 8 March1944 Claude Malraux, who was temporarily in charge of SALESMAN, was arrested and within hours all his contacts were blown.
UBA supports amateur radio operators in Belgium by sponsoring amateur radio operating awards, radio contests, and Amateur Radio Direction Finding competitions. The UBA also operates a QSL bureau for those members who regularly communicate with amateur radio operators in other countries. UBA represents the interests of Belgian amateur radio operators and shortwave listeners before Belgian and international telecommunications regulatory authorities. The UBA also publishes a monthly membership magazine called CQ QSO.
As one of the first four ships in her class, Admiral Isakov lacked a Vympel fire-control radar, and relied on manual targeting for the AK-630. Her electronic warfare equipment included the MRP-15-16 Zaliv and two sets each of the MRP-11-12 and MRP-13-14 direction finding systems, as well as the MRP-150 Gurzuf A and MRP-152 Gurzuf B radar jamming devices.
80 Nicholson had the only functional radar, though the merchant ship Toward could provide support with its High- frequency direction finding (HF/DF) set. Lea carried a British ASV aircraft radar with fixed antennae, but the coaxial cable to the antennae was repeatedly shorted by salt water spray.Hagerman (February 1976) p. 80 Edison had no depth charge throwers, and was limited to a linear pattern rolled off the stern.
This technique, known as radio direction finding (RDF), is useful but only moderately accurate. Measurements better than a few degrees are difficult with a small antenna, and because of the electrical characteristics, it is not always easy to make a larger version that might provide more accuracy. Moreover, the addition of a loop antenna may be difficult on smaller vehicles, or difficult to operate for those without a dedicated navigator.
The family seat, Bawdsey Manor, was requisitioned by the Devonshire Regiment during the First World War and returned to the family afterwards, but was later sold to the Air Ministry in 1936 for a new research station for the development of radio direction finding. In June 2018 the family seat since the late 19th century, Sutton Hall in Suffolk, was for sale by Sir Guy Quilter for £31.5m with 2,177 acres.
More depth charges were fitted on the upper deck of each side of the ship, allowing for about 200 in total; Royal Navy smoke floats were fitted above the depth charges in addition to the US Navy chemical smoke cylinders fitted to the stern of the Captains. A medium frequency direction finding antenna (MF/DF) was fitted in front of the bridge and a high-frequency direction finding (HF/DF, "Huffduff") Type FH 4 antenna was fitted on top of the mainmast; furthermore, a radio-receiving set tuned to the frequencies used for ship-to-ship communication by German U-boats and E-boats was fitted and a German-speaking rating carried. The Captains were eventually given Type 144 series Asdic (sonar) sets, an upgrade from the original Type 128D, and a Foxer was fitted to the aft of the Captains (and most other Atlantic escort vessels) during 1944 to counter the new acoustic torpedoes.
Gnomonic projections are used in seismic work because seismic waves tend to travel along great circles. They are also used by navies in plotting direction finding bearings, since radio signals travel along great circles. Meteors also travel along great circles, with the Gnomonic Atlas Brno 2000.0 being the IMO's recommended set of star charts for visual meteor observations. Aircraft and ship pilots use the projection to find the shortest route between start and destination.
Hellyer Brothers of Hull bought Vasari, had her converted into a fish factory ship to process halibut caught off Greenland and renamed her Arctic Queen. The rebuild changed her tonnages to and . By 1930 she was equipped with wireless direction finding equipment and by 1934 she was further equipped with an echo sounding device. In 1935 Hellyer Brothers sold Arctic Queen to the USSR, who renamed her Pishchevaya Industriya and based her in Vladivostok.
ELTs were first mandated in 1973 by FAA technical standard order (TSO-C91). The original TSO-C91, and updated TSO-C91A were officially deprecated as of February 2, 2009, when reception of the 121.5 MHz signal was deactivated on all of the SAR satellite, in favor of the C126 ELT models, with their 406 MHz Cospas-Sarsat beacons. However, the 121.5 MHz signal is still used for close- in direction finding of a downed aircraft.
Marshal Voroshilov was the first ship of her class completed with the MR-123 Vympel fire control radar for the AK-630, as the first four ships had not received it. Her electronic warfare equipment included the MRP-15-16 Zaliv and two sets each of the MRP-11-12 and MRP-13-14 direction finding systems, as well as the MRP-150 Gurzuf A and MRP-152 Gurzuf B radar jamming devices.
Admiral Oktyabrsky was the second ship of her class completed with the MR-123 Vympel fire control radar for the AK-630, as the first four ships had not received it. Her electronic warfare equipment included the MRP-15-16 Zaliv and two sets each of the MRP-11-12 and MRP-13-14 direction finding systems, as well as the MRP-150 Gurzuf A and MRP-152 Gurzuf B radar jamming devices.
The defensive armament consisted of an MG 131 in an A-Stand gun pod for the forward mounted machine gun position. One rotatable Drehlafette DL 131/1C (or E) gun mount in the B-stand was standard and later, MG 131 machine guns were added. Navigational direction-finding gear was also installed. The Peil G6 was added to locate targets and the FuBI 2H blind landing equipment was built in to help with night operations.
Even more advanced ASA equipment was on P-2V aircraft borrowed from the Navy, and called CEFLIEN LION or CRAZY CAT platforms. During the Vietnam era, six UH-1 helicopters were converted to SIGINT platforms, called EH-1 LEFT BANK aircraft and operated in direct support of combat aircraft. US tactical SIGINT aircraft include the EH-60A Quickfix helicopter, which has interception capabilities in the 1.5–150 MHz and direction finding between 20–76 MHz.
By 1938 she was equipped with wireless direction finding navigation equipment. The delivery of the modern motor ships in 1935 and in 1936 displaced Kościuszko from transatlantic service. She started to work the Constanţa – Haifa route in 1935 and a route to South America in October 1936. The delivery of the smaller motor ships and in 1939 made Kościuszko surplus to requirements so early in 1939 Gdynia America Line withdrew her from service.
Keeping the sensor away from the plane's engines and avionics helps eliminate interference from the carrying platform. At one time, reliance was placed on electronic warfare detection devices exploiting the submarine's need to perform radar sweeps and transmit responses to radio messages from home port. As frequency surveillance and direction finding became more sophisticated, these devices enjoyed some success. However, submariners soon learned not to rely on such transmitters in dangerous waters.
One of the last sports car races on the circuit was won by the future double World GP Champion Jim Clark. The last motor racing meeting at Edzell took place on Saturday, 20 June 1959. RAF Edzell reopened in 1960, forming part of the United States Navy global High Frequency Direction Finding (HFDF) network, used to track various targets around the world. Up to 3,000 personnel were said to have been stationed at RAF Edzell.
Until Japanese Army cryptosystems were broken later in 1943, the order of battle and movement information on the Japanese came purely from direction finding and traffic analysis. Traffic analysts began tracking Japanese units in near real time. A critical result was the identification of the movement, by sea, of two Japanese infantry divisions from Shanghai to New Guinea. Their convoy was intercepted by US submarines, causing almost complete destruction of these units.
By stretching a line between Borkum and List, composing the base of a triangle and simultaneously the chord, a circular direction finding coverage could be made over the North Sea. At its maximum, the coverage could direction-find the Royal Navy's Home Fleet which was located at Scapa Flow. At that range, a measurement accuracy of ±1° attributed to both stations, would have put location to within an accuracy of around 35 km diameter circle.
The IEEE Book series "The History of International Broadcasting" (Volume I) describes mobile shortwave relay stations used by the German propaganda ministry during WWII, to avoid them being located by radio direction finding and bombed by the Allies. They consisted of a generator truck, transmitter truck and an antenna truck, and are thought to have had a radiated power of about 50 kW. Radio Industry Zagreb (RIZ Transmitters) currently produces mobile shortwave transmitters.
Unfortunately, this transmission was detected by the American ships with their high-frequency direction finding ("Huff-Duff") equipment, which enabled them to pinpoint the submarine's location. The Francis M. Robinson reported a submerged contact at 19:00 on 13 May 1944. The destroyer escort engaged the contact with a full salvo from its forward-throwing Hedgehog mount, followed by five salvos of magnetic proximity fuzed depth charges. Four underwater explosions were detected.
On September 12, the Viet Minh established a Military Cryptographic Section, and, with their only reference a single copy of French Capitaine Roger Baudoin'sBaudoin French cryptographer Elements Cryptographic, and began to develop their own cryptosystems. Not surprisingly, these were very basic. By early 1946, they had established a network of radio systems, still transmitting with only minimal communications security. The French had a number of direction-finding stations, with about 40 technicians.
Fighter cover for this patrol was discontinued. The ACRP flights had been conducted by a detachment of Navy electronics squadron VQ-1, which relocated from Da Nang, South Vietnam, to Cubi Point Naval Air Station in the Philippines. Discussions among CINCPAC, Navy and Air Force operational commanders, about surveillance of the Gulf of Tonkin were underway, but came to no conclusion in 1973. Army Airborne Radio Direction Finding (ARDF) in South Vietnam was phased out.
There was VHF radio direction-finding equipment for locating vessels in trouble. The lifeboat also carried the latest DSC digital radio equipment for the vital radio communication used in search and rescue missions. The lifeboat was equipped with three VHF radios one of which was portable, together with an MF `long range`set. On the deck were powerful searchlights, and the lifeboat was also later equipped with image-intensifying night sight equipment.
The 6922d Security Group was activated in April 1970 at Clark Air Base in the Philippines. Initially, the group conducted operations through subordinate detachments ranging from Thailand through Japan. With the withdrawal of the United States from Vietnam, operations were substantially reduced, and by 1974 were limited to direction finding, and the group was reduced to the 6922d Security Squadron. Operations continued through June 1991, when Mount Pinatubo erupted, covering Clark with volcanic ash.
Douglas Morrell joined Marconi as an installation engineer in 1938, and would go on to travel around the British Empire throughout the war years installing radio direction-finding equipment as part of the war effort. After the war, he went on to work for Redifon as a sales engineer. It was with Redifon that he met Ray Brown, who would eventually join Calder Cunningham in starting Racal in 1950.Sir Ernest Harrison OBE.
Flying at over 5200 m (17,000 ft) they encounted unexpected high winds, and navigational difficulties were encountered because of cloud cover and British jamming of the German radio frequencies, which disabled radio direction finding. Damage was insignificant,Cole and Cheesman 1984, p. 198 and the wind made the return journey difficult: L 39, probably a victim of engine failure, was blown over France and eventually shot down by antiaircraft fire near Compiègne.
L-Tronics is a company based in Santa Barbara, California that specializes in the design and manufacture of direction finding (DF) equipment for search and rescue applications, used to locate signals originating from emergency locator beacons. These include Emergency Locator Transmitters (ELTs) used by aircraft, Emergency Position Indicator Radio Beacons (EPIRBs) used by marine vehicles, and Personal Locator Beacons (PLBs). One major operator of L-Tronics devices is the Civil Air Patrol.
The work of the long-range High frequency DF men in the signals monitoring service did not suffer from the work of the long-range DF men of the H-Dienst. For purposes of Peilkammando (DF centre) communication by telephone, in every DF station there was a loudspeaker with an amplifier. Peilkommando messages were picked up by a message centre radio operator. Telefunken DF sets with an Adcock antenna for direction finding were used.
TICOM Volume 5, p. 23 New Luftwaffe fixed intercept stations were founded in Munich, Münster, and Potsdam (Eiche) in 1937 and given the cover name of Weather Radio Receiving Stations () (abbr. W-Stellen). The Luftwaffe fixed intercept stations at first monitored only the air force point-to-point networks taken over by the Army. Since in peacetime, almost all countries sent their radio traffic in plaintext, the work was simple, and direction finding was unknown.
This same message enabled Germany to locate the 5th Infantry Division together with the French 68th Infantry, near Nieuwpoort and it also indicated the beginning of the evacuation of the British Expeditionary Force to England. On 26 May, intensive direction-finding operations confirmed the concentration of British, French and Belgian forces in the areas including Ghent, Kortrijk, Valenciennes, Lens, Béthune, Saint-Omer and Gravelines. Outside this area, no more enemy traffic was heard.
The Kazakhstan Federation of Radiosport and Radio Amateur (, Qazaqstannyń Radıosport jáne Radıoáýesqoı federatsııasy; ) is a national non-profit organization for amateur radio enthusiasts in Kazakhstan. KFRR promotes amateur radio in Kazakhstan by sponsoring amateur radio operating awards and radio contests. The KFRR organizes and supports Amateur Radio Direction Finding competitions and the Kazakhstan national ARDF team. The KFRR also represents the interests of Kazakhstan amateur radio operators before Kazakhstan and international telecommunications regulatory authorities.
The aircraft also has HF, VHF and UHF radios for voice and encrypted voice communications, plus direction finding. The crew may also use night vision goggles. The aircraft has no flaps and instead retains the top and bottom surface divebrakes of its sailplane ancestors. Maximum take-off weight of the RU-38A is 5300 lb (2404 kg) The RU-38A is designed to transit to its operational area with both engines operating.
With few exceptions, the hull, ramp, and power plant of the LCA remained the same throughout the war. Early on the coxswain's position was moved from aft to forward on the starboard side. Other particulars could vary greatly; some LCAs having Direction finding antenna loops, others Danforth anchors on vertical racks forward. The hatch layout on the stern deck varied, as did the placement and type of mooring bits, chocks, cleats, fairleads, and fuel caps.
Classic geological compasses that are of practical use combine two functions, direction finding and navigation (especially in remote areas), and the ability to measure strike and dip of bedding surfaces and/or metamorphic foliation planes. Structural geologists (i.e. those concerned with geometry and the pattern of relative movement) also have a need to measure the plunge and plunge direction of lineations. Compasses in common use include the Brunton compass and the Silva compass.
At least as early as 1938, Palembang was served by a civil airport at Talang Betutu, operating as a Customs Aerodrome equipped with wireless and direction finding equipment, and basic ground facilities. For Allies the airport was known as Palembang P1 (or just P1). The airport was re-built by the Japanese army during the Japanese occupation in 1942–1943. On July 15, 1963, it was a joint airfield, for civilian and military purposes.
There was VHF radio direction-finding equipment for locating vessels in trouble. The lifeboat also carried the latest DSC digital radio equipment for the vital radio communication used in search and rescue missions. The lifeboat was equipped with three VHF radios, one of which was portable, together with an MF `long range`set. On the deck were powerful searchlights, and the lifeboat was also later equipped with image-intensifying night sight equipment.
Traffic analysis from both long and short range units including intercepts which may not be from the enemy armies. 3. Checking and tactical evaluation of reports from Short Range units. 4. Traffic analysis, Direction finding evaluation, update of registry card index, NKVD evaluation and Russian Air force intercepts processing. 2. Cryptanalysis in the NAAS primarily meant the solution of unknown systems, the study of developments in known systems, and work on NKVD ciphers and processes.
This technique, known as radio direction finding (RDF), is useful but only moderately accurate. Measurements better than a few degrees are difficult with a small loop antenna, and because of the electrical characteristics, it is not always easy to make a larger version that might provide more accuracy. Moreover, the addition of a loop antenna may not be possible on smaller vehicles, or difficult to operate for those without a dedicated navigator.
A critical review came from Glenn Kenny of RogerEbert.com, who gave the film two stars out of four. Though he praised the performances and thought the story worked, Kenny criticized the social commentary and Phillips' direction, finding the film too derivative and believing its focus was "less in entertainment than in generating self-importance." In an analysis of the character Joker, Onmanorama's Sajesh Mohan wrote that the movie was cliché- ridden—the only original part being Joaquin Phoenix's acting.
A great amount of work was undertaken in the United States as part of the War Training Program in the areas of radio direction finding, pulsed linear networks, frequency modulation, vacuum tube circuits, transmission line theory and fundamentals of electromagnetic engineering. These studies were published shortly after the war in what became known as the 'Radio Communication Series' published by McGraw-Hill in 1946. In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer.
APRS beacon transmitter with GPS receiver. Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area. Data can include object Global Positioning System (GPS) coordinates, weather station telemetry, text messages, announcements, queries, and other telemetry. APRS data can be displayed on a map, which can show stations, objects, tracks of moving objects, weather stations, search and rescue data, and direction finding data.
Despite this, BdU had ordered temporary measures on 1 October, leading to an Enigma "blackout" at Bletchley Park. This lasted seven days, when Allied code- breakers re-gained access. The action had jeopardized Britain's fragile advantage in the intelligence war, and was saved only by the German navy's complacency concerning its Enigma code. Maertens report, which ran to 18 pages, dismissed the idea of a breach, attributing the discovery to radio direction finding, or to reports from neutral vessels.
The difference of the group time delay of a lightning pulse at adjacent frequencies is proportional to the distance between transmitter and receiver. Together with direction-finding methods, this allows locating lightning strikes up to distances of 10,000 km from their origin. Moreover, the eigenfrequencies of the Earth-ionospheric waveguide, the Schumann resonances at about 7.5 Hz, are used to determine the global thunderstorm activity.Volland, H. (ed) (1995) Handbook of Atmospheric Electrodynamics, CRC Press, Boca Raton, .
Urban direction finding (UDF) missions necessitate only a small kit of gear. But intensive mountain search and rescue can require packs that provide for up to 72 hours of operational supplies and tool for the location, rescue and extraction of lost or crashed parties. This gear includes the above, plus additional water, meals, and survival gear. Although a standardized list is provided by the national command, many teams modify the list to match the needs of the mission.
The radio equipment carried on course must be capable of receiving the signal being transmitted by the five transmitters and useful for radio direction finding. This includes a radio receiver that can tune in the specific frequency of transmission being used for the event, an attenuator or variable gain control, and a directional antenna. Directional antennas are more sensitive to radio signals arriving from some directions than others. Most equipment designs integrate all three components into one handheld device.
British Thomson-Houston of Rugby, Warwickshire built the turbo-generators and motors. The motors drove a pair of inward-rotating screw propellers. Strathnaver and Strathaird had three funnels but only the middle one served as a smoke stack: the first and third funnels were dummies. Strathnaver and Strathaird were each equipped with direction finding equipment, an echo sounding device and a gyrocompass As built, Strathnaver had accommodation for 498 first class and 668 tourist class passengers and 476 crew.
Beijing hosted 26 events: athletics, swimming, gymnastics, artistic gymnastics, weight lifting, fencing , judo, international style wrestling, boxing, modern pentathlon, equestrianism, Chinese-style wrestling, Go , speed skating, short track skating, cycling, navigation model, radio direction finding, parachute, soccer, basketball, table tennis, tennis, handball, hockey, and women's softball. Sichuan hosted 15 events: diving, water polo, synchronized swimming, fencing, shooting, archery, rowing, kayaking, swimming, water skiing, aviation model, volleyball, badminton, baseball, and martial arts. Qinhuangdao City hosted two events: sailing and windsurfing.
The Hayling Island inshore lifeboat Derrick Battle (B-829) just after launch during a lifeboat demonstration 3 km from West Wittering, West Sussex, Great Britain. The Lifeboat open day on Sunday 1 August 2009 The two current lifeboats are an lifeboat and a lifeboat. The Atlantic 85 inshore lifeboat is called Derrick Battle (B-829) and arrived on station on 26 February 2009. It is fitted with radar interlaced into the GPS system and VHF direction finding gear.
At the tactical force protection levels, Thales was awarded a contract to build SAEC (Station d'Appui Electronique de Contact) force protection stations, by the French defence procurement agency (DGA). The contract was awarded in 2004 and initial operational capability is expected by 2007. The SAEC is an armored vehicle carrying ELINT and the Thales XPLORER COMINT to complement EW platforms. It will have wideband acquisition, direction-finding and analysis sensors, for real-time monitoring and recording for subsequent analysis.
During the war, drifting mines and German U-boats damaged and sank a number of Icelandic vessels. Iceland's reliance on the sea, to provide nourishment and for trade, resulted in significant loss of life. In 1944, British Naval Intelligence built a group of five Marconi wireless direction-finding stations on the coast west of Reykjavík. The stations were part of a ring of similar groups located around the North Atlantic to locate wireless transmissions from U-boats .
U.S. Navy ships traditionally avoid using their radios to prevent adversaries from locating them by direction finding. The Navy also needs to maintain traffic security, so it has radio stations constantly broadcasting a stream of coded messages. During and after World War II, Navy ships copied these fleet broadcasts and used specialized call sign encryption devices to figure out which messages were intended for them. The messages would then be decoded off line using SIGABA or KL-7 equipment.
The U.S. Naval Research Laboratory, the first modern research institution created within the United States Navy, began operations at 1100 on 2 July 1923. The Laboratory's two original divisions – Radio and Sound – performed research in the fields of high-frequency radio and underwater sound propagation. They produced communications equipment, direction-finding devices, sonar sets, and the first practical radar equipment built in the United States. They performed basic research, participating in the discovery and early exploration of the ionosphere.
The battle of Jutland was eventually fought but its lateness in the day allowed the enemy to escape. Jellicoe's faith in cryptographic intelligence was also shaken by a decrypted report that placed the German cruiser SMS Regensburg near him, during the Battle of Jutland. It turned out that the navigator on the Ravensburg was off by in his position calculation. During Jutland, there was limited use of direction finding on fleet vessels, but most information came from shore stations.
Boat with direction finding birds to find land. Model of Mohenjo-daro seal, 2500-1750 BCE. Judging from the dispersal of Indus civilisation artefacts, the trade networks economically integrated a huge area, including portions of Afghanistan, the coastal regions of Persia, northern and western India, and Mesopotamia, leading to the development of Indus-Mesopotamia relations. Studies of tooth enamel from individuals buried at Harappa suggest that some residents had migrated to the city from beyond the Indus Valley.
The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, the Huons use three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
RNZAF Station Waipapakauri was a Royal New Zealand Air Force station located at Waipapakauri, 14 km north of Kaitaia, Northland Region, New Zealand. Originally established in 1933 as a small local aerodrome, it was commandeered as an air force base by the RNZAF at the outbreak of war in 1939. The New Zealand Division of the Royal Navy established a radio intercept and direction finding (D/F) station here as part of a network throughout the country.
There are many applications of spectral estimation of multi-D signals such as classification of signals as low pass, high pass, pass band and stop band. It is also used in compression and coding of audio and video signals, beam forming and direction finding in radars, Seismic data estimation and processing, array of sensors and antennas and vibrational analysis. In the field of radio astronomy, it is used to synchronize the outputs of an array of telescopes.
The crews were highly experienced in night operations and selected to help lead the attacks under the command of Major Friedrich Kless. The three units operated in unison often: KGr 100 illuminated the target with incendiaries and the later formations dropped high explosive bombs to destroy water mains and impede fire-fighting efforts.Wakefield 1999, p. 72. II./KG 55 used Knickebein and Direction finding methods when British countermeasures from No. 80 Wing RAF did not impede them.
Around the edge of the octagon are the remnants of a reinforced parapet, which has long been removed. There are also signs of a Fletton brick wall running westward away from the raised area. The octagonal shape of the base indicates that a direction-finding station operator's hut stood there. It would have consisted of a double-skinned wooden structure in which the cavity was filled with shingle designed to make them "splinter proof" or "bulletproof".
The minesweeper departed Pearl Harbor on 5 May 1941, bound for the Asiatic Fleet. En route, the minecraft plane-guarded at prearranged stations, serving as a direction-finding station for patrol planes flying to the Philippines to reinforce the Asiatic Fleet's air wing—Patrol Wing 10. After touching briefly at Guam, in the Marianas, on 23 May, Whippoorwill reached Manila on the 30th. There, she became part of Mine Division 9, Mine Squadron 3, Asiatic Fleet.
Pickard is well known for his early inventions in connection with loop aerials, direction-finding systems and static mitigating devices used at Otter Cliffs during the war. His technical achievements and illustrations of equipment at Otter Cliffs during the war were documented in detail in the Proceedings of the IRE. Edmond Bruce, a Navy enlisted man, served as chief electrician for the transatlantic receiver during the war. He later became a widely recognized radio engineer and inventor.
The motorized very close- range DF troops were equipped with VHF intercept receivers of the Type V configuration, and for very close-range DF work, they used belt DF and different kinds of suitcase DF units.IF-176, p. 23. The Belt Direction finding unit was a small, flat apparatus which can be worn as a belt under a jacket or coat without being noticed. The power supply is small enough to be carried in the trousers pocket.
Hubbard sailed on 26 December 1944 with other destroyer escorts to hunt down weather-reporting U-boats in the Atlantic. Equipped with the latest direction-finding gear, the ships scouted the suspected area until they came upon on 16 January 1945. Depth charge attacks sank the German marauder late that morning. The ships arrived New York on 6 February and, after additional training in Casco Bay, sailed again to search for submarines 4 April from NS Argentia, Newfoundland.
In return, the British pledged to prepare two full sets of Zygalski sheets for all 60 possible wheel orders. The French contingent consisted of Major Gustave Bertrand, the French radio-intelligence and cryptology chief, and Capt. Henri Braquenié of the French Air Force staff. The British sent Commander Alastair Denniston, head of Britain's Government Code and Cypher School, Dilly Knox, chief British cryptanalyst and Commander Humphrey Sandwith, head of the Royal Navy's intercept and direction-finding stations.
9 Wing includes the 9 Air Reserve Augmentation Flight. It augments and support the operations, administrative and technical functions of the base. Its Airfield Engineers Flight provides trained engineer reservists from various trades to support UN and Canadian Forces deployments worldwide. CFB Gander is also host to the Leitrim Detachment which operates and maintains signals intelligence and utilizes a Wullenweber AN/FRD-10 circularly disposed antenna array for High-frequency direction finding of high priority targets.
The first generation of Japanese immigrants, the Issei, came in 1883. During World War II, Japanese-American residents of Bainbridge Island were the first to be sent to internment camps, an event commemorated by the Bainbridge Island Japanese American Exclusion Memorial, which opened in 2011. They were held by the US government through the duration of the war for fear of espionage. A High-frequency direction finding (HFDF) station was established here by the Navy during the war.
British Thomson-Houston of Rugby, Warwickshire built the turbo-generators and motors. The motors drove a pair of inward-rotating screw propellers. Like Strathnaver, Strathaird had three funnels but only the middle one served as a smoke stack: the first and third funnels were dummies. Strathaird and Strathnaver were each equipped with direction finding equipment, an echo sounding device and a gyrocompass As built, Strathaird had accommodation for 498 first class and 668 tourist class passengers.
Following their training at Wunstorf, the two were sent to the Nachtjagdschule 1 (1st night fighter school) at Schleißheim near Munich, formerly the Zerstörerschule 1 (ZS 1—1st destroyer school), to learn the rudiments of night-fighting. The night fighter training was carried out on the Ar 96, the Fw 58 and the Messerschmitt Bf 110. Training at night focused on night takeoffs and landings, cooperation with searchlights, radio-beacon direction finding and cross country flights.
The lifeboat has a variety of equipment to help rescue vessels and save lives. The kit includes advanced medical kit including an automatic external defibrillator (AED) and oxygen, search lights and thermal imaging cameras. There is also a VHF direction-finding equipment for homing in on a casualty vessel’s radio transmissions, a chart plotter, tow lines, radar and depth sounder. The Lifeboat also features VHF radios for communications with the Coastguard, Gosport Lifeboat Station and casualties.
The Belarusian Federation of Radioamateurs and Radiosportsmen () is a national non-profit organization for amateur radio enthusiasts in Belarus. The organization uses BFRR as its acronym, based on the standard Romanization of the Belarusian name of the organization. The name of the organization reflects an early purpose of the organization: to support radiosport activities within Belarus. In addition to High Speed Telegraphy and Amateur Radio Direction Finding, BFRR now supports a wide variety of amateur radio activities.
The Association of Radio Amateurs of Slovenia (, acronym ZRS) is the national non-profit organization for amateur radio enthusiasts in Slovenia. Key membership benefits of ZRS include the sponsorship of amateur radio operating awards and radio contests. ZRS also supports local competitions in Amateur Radio Direction Finding as well as a national team that travels to regional and world championship events. ZRS represents the interests of Slovenian amateur radio operators before Slovenian and international telecommunications regulatory authorities.
Originally, Mission Chrysler was to establish a show of authority and liaison in the area in anticipation of an early Axis capitulation. When this did not happen, the mission was changed to assist the partisan units with arms and supplies. German forces went after the Chrysler men, who had several narrow escapes from anti-partisan sweeps. At one point, the Germans pinpointed the OSS transmitter to within 100 yards, but partisans intercepted three Germans and a Swiss interpreter with direction-finding gear.
There is a diverse vocabulary associated with the hobby, many words and phrases having been copied from the original American service. Few of these words are used in general conversation in the UK, and they serve equally as a reminder of the hobby’s American origins. An extensive list of such words and their associated definitions can be found here. :Foxhunts Not to be confused with fox hunting : A fox hunt is a direction finding activity using cars and vans fitted with CB radios.
Once there, the night fighters were ordered to transmit direction-finding signals to attract other night fighters. While semi-unguided, the radar operators and night fighter command retained some control over operations with success in August; amounting to 250 aircraft claimed shot down on all fronts. The success was offset by losses of 40 killed in the night fighter arm, with only 28 replacements in August. 61 twin-engine night fighters were lost during the month, but only 59 were replaced.
The German captain's report coincided with reports of a decrease in sightings and a period of tension between Dönitz and Raeder. The number of U-boats in the Atlantic, by logic, should have increased, not lowered the number of sightings and the reasons for this made Dönitz uneasy. Despite several investigations, the conclusions of the BdU staff was that Engima was impenetrable. His signals officer responded to the U-459 incident with answers ranging from coincidence, direction finding to Italian treachery.
Members of the USAFSS included morse intercept operators, voice intercept and linguists, non-morse intercept operators, direction finding (DF) equipment operators, and analysts. In June, 1951, the largest U.S. air victory in the Korean War to that date was facilitated by tactical data from a USAFSS detachment, leading to a US air victory when F-86s from Inchon shot down 11 enemy planes. In 1962, the first significant intelligence data on Soviet Union involvement in Cuba was provided by the USAFSS.
ARDF events use radio frequencies on either the two-meter or eighty-meter amateur radio bands. These two bands were chosen because of their universal availability to amateur radio licensees in all countries. The radio equipment carried by competitors on a course must be capable of receiving the signal being transmitted by the five transmitters and useful for radio direction finding, including a radio receiver, attenuator, and directional antenna. Most equipment designs integrate all three components into one handheld device.
The damage inflicted upon the Allies by German U-boats during World War II made the need for sonar a priority. With millions of tons of shipping being sunk in the Atlantic, there was a need to locate submarines so that they could be sunk or prevented from attacking. Sonar was installed on a number of ships along with radar and high-frequency direction finding ("Huff-Duff") to detect surfaced submarines. While sonar was a primitive system, it was constantly improved.
From the earliest days of radio technology, signals had been used for navigation using the radio direction finding (RDF) technique. RDF can determine the bearing to a radio transmitter, and several such measurements can be combined to produce a radio fix, allowing the receiver's position to be calculated. Given some basic changes to the broadcast signal, it was possible for the receiver to determine its location using a single station. The UK pioneered one such service in the form of the Orfordness Beacon.
He learned code and cipher theories from an Austrian Professor named Fiegl, and he also set up an intensive cooperation network with the Polish intelligence. He learned about radio direction finding vehicles in Italy and managed to get some to Finland. Beginning from 1927, the newly created Finnish Radio Intelligence followed the movements and the radio traffic of the Soviet Red Fleet. The first Soviet Red Fleet codes were broken in 1934 and soon more followed, including foreign diplomatic codes.
The machine was used in high-altitude de-icing tests, and the aircraft was tested with Lichtenstein BCR and Bernhardine radar. In August ten of these aircraft were constructed, and between 27 and 31 August, they were fitted with their Schräge Musik at Erprobungsstelle Tarnewitz and Wismar Testing Facilities. The tenth N variant, designated N-0, underwent radio trials. The machine was tested with the Peil G VI/APZ 6, a later and more sophisticated variant automatic direction-finding equipment.
Airfields were redeveloped across NSW including Cootamundra as well as Mascot, Narromine, Tamworth, Narrandera, Temora, Uranquinty, Deniliquin, Parkes, Camden, Evans Head, Wagga Wagga. By 1940 the Royal Australian Air Force had completely taken over the control of the Cootamundra aerodrome and Squadron Numbers 60 and 73 operated from the base. A direction finding station was also built at Cootamundra to service the radio communications system. This system was considered vital in the detection of enemy raiders and for providing data in battle situations.
All broadcast stations throughout the country would be constantly listening to an upstream station and repeat the message, thus passing it from station to station. After broadcasting the message, all radio communications would cease except for two designated lower power AM frequencies (640 and 1240 kHz). This was designed to prevent enemy planes from using transmitters as navigation aids for direction finding. The later threat of ICBMs (which used internal guidance) made this obsolete, and CONELRAD was replaced in 1963.
An ARHAB flight consists of a balloon, a recovery parachute, and a payload of one or more packages. The payload normally contains an amateur radio transmitter that permits tracking of the flight to its landing for recovery. Most flights use an Automatic Packet Reporting System (APRS) tracker which gets its position from a Global Positioning System (GPS) receiver and converts it to a digital radio transmission. Other flights may use an analog beacon and are tracked using radio direction finding techniques.
As of 2013, UNHRD also expanded its warehouses and premises in this facility in addition to its original assets in Brindisi Military Airport. The 6917th Electronic Security Group and 7275 Air Base Group were stationed on San Vito. The US Navy also played a large part in the interception and decoding of intelligence and High Frequency Directional Finding. The base also hosted a small U.S. Army 9-man radio direction finding detachment reporting to the 600th USASA Company in Vicenza, Italy.
The first mechanically scanned phased array radar (using a rotating Yagi antenna) was demonstrated in the 1930s. The first electronically scanned radars used electromechanical devices (such as mechanical tuners or switches) to steer the antenna's beam. Germany built the Wullenweber circular array for direction finding during the early years of World War II. The Wullenweber could electronically scan the horizon 360° and determine the direction of any signal with reasonably good accuracy. Circular arrays were enhanced during the Cold War for eavesdropping purposes.
Air Force Auxiliary, Civil Air Patrol Observer Badge The title "Observer" is still used regularly in the U.S. Air Force Auxiliary, better known as the Civil Air Patrol. Civil Air Patrol observers may act as the mission commander for aircrews engaged in search and rescue, homeland defense reconnaissance, or other Air Force-authorized missions, serving as the liaison between the sortie and mission base. Observers are trained in air navigation, radio communications, and other technical subjects such as aerial direction finding.
It began with Hellcat fighters strafing the anti-aircraft batteries while Wildcats attacked the battleship. The fighters also attacked German ships in Kaafjord and a radio or radio direction finding station. The Barracudas executed their dive bombing attack at 6:36 am and struck Tirpitz with a 1,600-pound bomb and four 500-pound bombs within a minute.Bishop (2012), p. 306 The German defences at Kaafjord received little warning of the incoming raid, and the smokescreen hid the British aircraft from sight.
It also was the first radio receiver in the world. Ground-based and mobile detectors calculate the direction and severity of lightning from the current location using radio direction-finding techniques along with an analysis of the characteristic frequencies emitted by lightning. Ground-based systems use triangulation from multiple locations to determine distance, while mobile systems estimate distance using signal frequency and attenuation. Space-based detectors on satellites can be used to locate lightning range, bearing and intensity by direct observation.
Over the years the original Q-codes were modified to reflect changes in radio practice. For example, QSW / QSX originally stood for, "Shall I increase / decrease my spark frequency?", but in the 1920s spark-gap transmitters were gradually being banned from land stations, making that meaning obsolete. By the 1970s, the Post Office Handbook for Radio Operators listed over a hundred Q-codes, covering a wide range of subjects including radio procedures, meteorology, radio direction finding, and search and rescue.
Radar (Type 286, later replaced by Type 290 and Type 271) was fitted during the war, as was HF/DF radio direction-finding gear.Preston 1971, plate 13 caption, between p. 64 and 65. Conversion to a short-range escort involved removal of two more 4.7 inch guns and a bank of torpedo tubes, with the forward gun replaced by a Hedgehog anti-submarine mortar, and the aft gun and tubes removed to allow a heavy depth charge armament of 70 charges.
Spherical mirrors can be used for direction finding by moving the sensor rather than the mirror; another unusual example is the Arecibo Observatory.The Arecibo Observatory - Past, Present and Future Acoustic mirrors had a limited effectiveness, and the increasing speed of aircraft in the 1930s meant that they would already be too close to engage by the time they had been detected. The development of radar put an end to further experimentation with the technique. Nevertheless, there were long- lasting benefits.
It is capable of being beached in an emergency without sustaining damage to engines or steering gear. The Atlantic 85 is fitted with radar and VHF direction finding equipment and can be operated safely in daylight in a force 6/7 and at night in a force 5/6. The Atlantic 85 also has intercom communications between the crew and VHF radio via their helmets, DGPS & Chartplotter. It also carries a searchlight, night-vision equipment and illuminating paraflares for night-time operations.
Rescue 21 will provide the United States with a 21st-century maritime command, control, and communications (C3) system that encompasses the entire United States. By replacing outdated technology with a fully integrated C3 system, Rescue 21 improves on the NDRS with the following enhancements: interoperability, direction-finding equipment with 2 degrees Root Mean Square of accuracy, enhanced clarity of distress calls, simultaneous channel monitoring, upgraded playback and recording feature for distress calls, reduced coverage gaps, and supporting Digital Selective Calling (DSC).
The modern development of the metal detector began in the 1920s. Gerhard Fischer had developed a system of radio direction- finding, which was to be used for accurate navigation. The system worked extremely well, but Fischer noticed there were anomalies in areas where the terrain contained ore-bearing rocks. He reasoned that if a radio beam could be distorted by metal, then it should be possible to design a machine which would detect metal using a search coil resonating at a radio frequency.
Later that month, she joined the destroyers and in escorting Convoy ONS 138 on a transatlantic voyage from Liverpool to Halifax, Nova Scotia, Canada; the convoy avoided attack by German submarines by exploiting radio direction-finding information to alter course around them. In November 1942, Whitehall returned to the United Kingdom as part of the escort for a convoy making the reverse trip. During 1942, Whitehall was "adopted" by the civil community of Cheltenham, Gloucestershire, in a Warship Week national savings campaign.
The submarines sank two of the convoys merchant ships that day, and Whitehall, Hesperus, and the corvette joined forces to drive off and . Hesperus damaged and sank on 11–12 May, while Whitehall pursued two radio direction-finding contacts on the afternoon of 12 May, attacking one submarine with depth charges and another with gunfire and depth charges without sinking them. Syrett, David, The Defeat of the German U-Boats: The Battle of the Atlantic, University of South Carolina, 1994, , p. 114.
The station was constructed in 1942 as Naval Radio Station (NRS) Masset and became active on 23 February 1943. NRS Masset was used as a high-frequency direction finding (HFDF) intercept station and a relay station for ship-to-shore communications. At the end of World War II NRS Masset was placed into caretaker status until reactivation in 1949, however an earthquake damaged the station and operations were suspended until 1951 when Masset became part of the military's SUPRAD (supplementary radio) system.
Frequency agility is the ability of a radar system to quickly shift its operating frequency to account for atmospheric effects, jamming, mutual interference with friendly sources, or to make it more difficult to locate the radar broadcaster through radio direction finding. The term can also be applied to other fields, including lasers or traditional radio transceivers using frequency-division multiplexing, but it remains most closely associated with the radar field and these other roles generally use the more generic term "frequency hopping".
At the end of the war AWS-8 maintained detachments at Zamami and Point Dog providing aerial surveillance and direction finding within their assigned sectors. On October 8 & 9, 1945 the squadron weathered Typhoon Louise which caused immense destruction at both sites. In the later half of October 1945, the detachment on Zamami departed and the squadron was consolidated at Point Dog. This marked the first time the squadron was together in one location since they had departed MCAS Ewa, Hawaii in February.
The deck gun became less effective as convoys became larger and better equipped, and merchant ships were armed. Surfacing also became dangerous in the vicinity of a convoy because of improvements in radar and direction finding. (See Defensively equipped merchant ships (DEMS) and United States Navy Armed Guard). German U-boat deck guns were eventually removed on the order of the supreme commander of the U-boat Arm (BdU) during World War II, and those deck guns that remained were no longer manned.
Performance with the Twin-Wasps was marginally improved: maximum speed went up from and the service ceiling increased from . Normal range was reduced from .Robertson, 1976, pp=30–31, 79 Other modifications introduced on the Mk II used on late Mk Is included replacing the elongated direction finding antenna with a loop aerial enclosed in a clear, tear-drop fairing on the top of the cabin. ASV Mk III was added with yagi antennae under the nose and wings and a Bristol B1.
The program to install and operate the radio direction finding network was known as Bullseye, Clarinet Bullseye and Classic Bullseye at various points over its life cycle. The word Classic was likely added later when permanently assigned "first words" were created for two-word nicknames. Classic was the word used to designate programs related to the Naval Security Group and Clarinet was used for programs related to the Chief of Naval Operations. Classic Bullseye was also related to the Centerboard and Flaghoist programs.
ESL was a leader in developing strategic signal processing systems and a prominent supplier of tactical reconnaissance and direction-finding systems to the U. S. military. These systems provided integrated real-time intelligence. Most of TRW—including ESL—was acquired by the Northrop Grumman Corporation in December 2002. ESL primarily supplied domestic intelligence agencies, NASA and the U.S. military, but had certain direct relations with the North Atlantic Treaty Organization (NATO) and also provided some services for a variety of state agencies.
This caused the signal to trace out a pattern on the display that could be used to determine the direction of the transmission almost instantly. In the UK, the high-frequency direction finding (HFDF or “huff-duff”) system largely had displaced BTDF by about 1943. HFDF used balanced amplifiers that fed directly into a CRT to instantly display the direction directly from the incoming signal, requiring no mechanical movement of any sort. This allowed even the most fleeting signals to be captured and located.
As a seafaring nation, Japan had an early interest in wireless (radio) communications. The first known use of wireless telegraphy in warfare at sea was by the Imperial Japanese Navy, in defeating the Russian Imperial Fleet in 1904 at the Battle of Port Arthur. There was an early interest in equipment for radio direction-finding, for use in both navigation and military surveillance. The Imperial Navy developed an excellent receiver for this purpose in 1921, and soon most of the Japanese warships had this equipment.
Cammell Laird of Birkenhead, on the Wirral in England built all five Lady-liners, and completed Lady Hawkins in November 1928. Lady Hawkins was an oil-burner, with a set of four Cammell Laird steam turbines driving the propeller shafts to her twin screws by single-reduction gearing. She had three passenger decks, and by 1931 she was equipped with a direction finding device. CN introduced the liners which became known as "Lady Boats" for mail, freight and passenger traffic between Canada, Bermuda and the Caribbean.
Dawn on 12 September was overcast clear underneath, with a north- westerly breeze when a BV 138 dropped below the cloud. Four Sea Hurricanes took off from Avenger but failed to shoot down the shadower, which flew back into the clouds. Sea Hurricanes were armed with rifle calibre machine-guns and hits often failed to penetrate. During the day, escorts' High-frequency direction finding equipment (Huff-Duff) detected U-boat wireless transmissions and the escorts made many depth charge attacks, driving off several U-boats.
Galeta Island, Panama The Wullenweber (the original name introduced by Dr. Hans Rindfleisch was Wullenwever) is a type of Circularly Disposed Antenna Array (CDAA) sometimes referred to as a Circularly Disposed Dipole Array (CDDA). It is a large circular antenna array used for radio direction finding. It was used by the military to triangulate radio signals for radio navigation, intelligence gathering and search and rescue. Because its huge circular reflecting screen looks like a circular fence, the antenna has been colloquially referred to as the elephant cage.
The location of each transmitter will be indicated on the map with a circle. The transmitter does not need to be exactly at the circle's center or even located inside the circle, but one should be able to receive its transmissions everywhere within the area indicated by the circle. A competitor must use orienteering skills to navigate to the area of the circle on the map and only then use radio direction finding skills to locate the very low power transmitter.Victorian ARDF Group (2009).
After sea trials and commissioning in November 1945 Loch Arkaig sailed to the Clyde in December for modifications to stiffen her hull. In January 1946 the ship carried out Squid anti-submarine mortar and radio direction finding calibration, before joining the Flotilla at Derry to take part in "Operation Deadlight". She sank the U-boat on 16 February, and on 19 February with her Squid mortar and Shark 4-inch projectiles. U-3514 was the last U-boat to be sunk in "Operation Deadlight".
BORAP is an ELINT/ESM system designed and developed by the ERA company in the Czech Republic, manufacturers of the VERA system. BORAP is designed for the detection, identification, location and tracking of air, ground and naval targets using an advanced wideband interferometric direction finding technique complemented with a high performance ELINT analysis subsystem. Two or more BORAP stations locate emitters through triangulation. It can alternatively be used in combination with VERA systems to locate targets by the intersection of lines of bearing with hyperbola.
Physically, the basic Prophet platform is built around a mounted AN/PRD-13(V)2 direction-finding (DF) system designed to provide force protection in a DS role to the maneuver brigade. This system operates in the HF, VHF and UHF spectra. It provides line-of-bearing (LOB) data and intercept on unencrypted, single-channel push-to-talk transmissions. It can be put into subassemblies that can be carried by a four-man team individual soldiers, although the more common deployment will be in an M1097 HMMWV.
In addition to the AN/SLQ-32, s are in the process of evaluating an open-architecture Integrated Radar/Optical Sighting and Surveillance System (IROS3) and Ship Protection system, currently including an AN/SPS-73 radar, an electro-optical/infrared sensor, acoustic sensors and spotlights, coupled with remotely controlled machine guns. Standardized USN systems go beyond simple direction finding and into COMINT. The AN/SLR-25 is a passive cryptologic exploitation system principally for tactical use, but that can make contributions to higher levels of intelligence.
In the early 1920s a radio direction finding station was located there that helped give accurate position reports for aircraft flying to Croydon airport. The base became disused in the early 1930s after the crash of the R101 when all work stopped in Britain on airships, although it continued as an RAF property until 1958. During World War II it was a dump for crashed aircraft from all over the east of England; parts were salvaged for reuse. Munitions testing was also conducted on the site.
Watt worked at the RAF's Met Office in Aldershot, but in 1924 they decided to return the location to use for the RAF. In July 1924 Watt moved to a new location at Ditton Park near Slough. This site already hosted the National Physical Laboratory (NPL) Radio Section research site. Watt was involved in the Atmospherics branch, making basic studies in the propagation of radio signals through the atmosphere, while the NPL were involved in field strength measurements in the field and direction finding investigations.
The AFCS allows the operation of a four-axis (pitch, roll, yaw and collective) autopilot and the automatic stabilisation system, and is linked in with the aircraft's flight management systems.Moir and Seabridge 2008, pp. 343–345. The AFCS, manufactured by Smiths Aerospace, is a dual-duplex system using two flight computers to provide redundancy and fault-tolerance. The AW101's navigation system includes a GPS receiver and inertial navigation system, VHF omnidirectional radio range (VOR), instrument landing system (ILS), TACAN, and automatic direction finding.
The radio direction finding station at Darwin expected to be in contact with Earhart when she arrived there, but Earhart stated that the RDF was not functioning; the problem was a blown fuse. During a test flight at Lae, Earhart could hear radio signals, but she failed to obtain an RDF bearing. While apparently near Howland Island, Earhart reported receiving a 7500 kHz signal from Itasca, but she was unable to obtain an RDF bearing. The antennas and their connections on the Electra are not certain.
With the radio contact, the plane should be able to use radio direction finding (RDF) to head directly for the Itasca and Howland. Unfortunately, the plane was not receiving a radio signal from Itasca, so it would be unable to determine an RDF bearing to the ship. Although Itasca was receiving HF radio signals from the plane, it did not have HF RDF equipment, so it could not determine a bearing to the plane. The communications going to the plane were almost non- existent.
Through a series of misunderstandings or errors (the details of which are still controversial), the final approach to Howland Island using radio navigation was not successful. Fred Noonan had earlier written about problems affecting the accuracy of radio direction finding in navigation. Another cited cause of possible confusion was that the Itasca and Earhart planned their communication schedule using time systems set a half- hour apart, with Earhart using Greenwich Civil Time (GCT) and the Itasca under a Naval time zone designation system.Hoversten 2007, pp. 22–23.
Here they underwent a refit to replace unsatisfactory US Navy equipment. The ships were fitted with an Admiralty design gyro compass and depth charge arrangements, as well as receiving the latest sonar systems and a Royal Navy design radio direction finding outfit. The refit lasted until late February, and on its completion on 28 February Kempthorne was nominated to deploy with the 5th Escort Group in the Western Approaches Command. Further sea trials were carried out in March, followed by a period of work-up at Tobermory.
The report stated that Admiralty was not using Enigma to locate U-boat groups. The team believed it was the U-boat wolfpacks themselves, because they had stayed in position, in the same region of the ocean, in the same formation for several days and nights. The lack of movement along with their sending periodic signals back to HQ made them visible and vulnerable to Allied direction finding. The signals from D/F were assumed to be the source, not cryptanalysis of Enigma messages.
The basic principle of the correlative interferometer consists in comparing the measured phase differences with the phase differences obtained for a DF antenna system of known configuration at a known wave angle (reference data set). The comparison is made for different azimuth values of the reference data set, the bearing is obtained from the data for which the correlation coefficient is at a maximum. If the direction finding antenna elements have a directional antenna pattern, then the amplitude may be included in the comparison.
The Radio Direction Finding records room was next door and kept records of the signals' exact locations of origin. In 1940 the use of the hall for all of these different functions allowed for the required specially designed wireless set rooms to be constructed in the grounds of the hall. This was instead of converting the existing rooms within the building for this purpose. A field to the north of the hall was chosen as the ideal location to construct the new set huts.
Epstein was the son of mathematician Paul Epstein and Alice Betty (née Wiesengrund). On his mother's side he was thus related to Theodor Adorno, since Alice Betty was Adorno's aunt.Stefan Müller-Doohm, Adorno: a biography, (tr. Rodney Livingstone), Polity, 2005 p.188 He graduated to Heidelberg University where his studies were interrupted by the outbreak of World War I. He served in a sound-direction-finding unit (Schallmesstrupp)on the Western Front, and took part in General Ludendorff's Kaiserschlacht or final offensive in 1918.
Early radio direction finding (RDF) solutions used highly directional antennas with sharp "nulls" in the reception pattern. The operator rotated the antenna looking for points where the signal either reached a maximum, or more commonly, suddenly disappeared or "nulled". A common RDF antenna design is the loop antenna, which is simply a loop of wire with a small gap in the circle, typically arranged to rotate around the vertical axis with the gap at the bottom. Some systems used dipole antennas instead of loops.
Before the 1930s, radio signals were generally in what would today be known as the longwave spectrum. For the effective reception of these signals, very large antennas are needed. Direction finding with rotating antennas is difficult at these wavelengths due to the size of the antennas. A great advance in RDF technique was introduced in the form of the Bellini-Tosi direction finder system, which replaced the rotation of the antenna with the rotation of a small coil of wire connected to two non-moving antennas.
Richelieu then steamed north to Toulon on 1 October where she was visited again by Lemonnier, but the shipyard there was in ruins, so she moved to Casablanca on 10 October to be refitted. In addition to the hull cleaning and boiler repairs, she had new fire control and search radars installed, including a US SG-1 search radar, British Type-281B air search radar, and Type-285P fire control radars, in addition to other equipment, including an FV1 jammer and high-frequency direction finding gear.
In November she was transferred to the Liverpool Sloop Division for Atlantic convoy escort duty. In June 1941 she was transferred to the 41st Escort Group based at Derry for the defence of convoys between the UK and Freetown. In early 1942 Type 271 radar and HF/DF direction finding equipment was fitted. In October Aberdeen escorted military convoys to Gibraltar in preparation for the landings in North Africa ("Operation Torch"), and on 8 November was deployed off Oran in support of the landings.
After the last sinking at the end of April, Leonardo da Vinci turned for home. On 22 May 1943, off the coast of Spain, it unwisely signalled its intention to head for Bordeaux on completion of its patrol. Its position having been fixed by direction-finding, on 23 May the destroyer and the frigate (both escorts to convoys WS-30 and KMF-15) subjected the submarine to an intense depth charge attack and sank it west of Vigo at an estimated position of . There were no survivors.
Horner (1982). p. 242. The Australian Army and RAAF also provided most of the Allied radio interception capability in the SWPA, and the number of Australian radio interception units was greatly expanded between 1942 and 1945. Central Bureau broke a number of Japanese codes and the intelligence gained from these decryptions and radio direction finding greatly assisted Allied forces in the SWPA.Clarke (2005). pp. 48–51. 2/3rd Independent Company in New Guinea during July 1943 Australian special forces played a significant role in the Pacific War.
The transmitter does not need to be exactly at the circle's center or even located inside the circle, but one should be able to receive its transmissions everywhere within the area indicated by the circle. A competitor must use orienteering skills to navigate to the area of the circle on the map and then use radio direction finding skills to locate the very low power transmitter. Fox Oring has increased popularity and it's now an official part of the International Amateur Radio Union Region 1 championship.
KW-37 transmitter on display at the Naval History museum at La Spezia, Italy. Remington Rand format punch card similar to the type used by NSA to distribute keys. The KW-37, code named JASON, was an encryption system developed In the 1950s by the U.S. National Security Agency to protect fleet broadcasts of the U.S. Navy. Naval doctrine calls for warships at sea to maintain radio silence to the maximum extent possible to prevent ships from being located by potential adversaries using radio direction finding.
Although some aircrew training took place in other Commonwealth countries, Canada's training facilities supplied the majority of aircrew for overseas operational service.Hatch 1983, p. 109. Schools included initial training schools, elementary flying training schools, service flying training schools, flying instructor's schools, general reconnaissance schools, operational training units, wireless schools, bombing and gunnery schools, a flight engineers' school, air navigation schools, air observer schools, radio direction finding (radar) schools, specialist schools, and a few supplementary schools. The BCATP contributed over 130,000 aircrew to the war effort.
On 28 November U-238 picked up two allied airmen whose aircraft had crashed. U-238’s skipper, Horst Hepp, radioed a long account of his interrogation of them, which was intercepted and tracked by HF/DF (radio direction finding). Hepp was meanwhile ordered to meet U-764, which was returning to base, in order to transfer the prisoners. Allied forces were sent to intercept the two U-boats, with a view to rescuing the airmen, and prevent the two boats from getting away.
Aerial feeders ran underground, and surfaced in the centre of the hut where they connected to a direction finding goniometer and a wireless receiver, that allowed the bearing of the signal source to be measured. In the UK some operators were located in an underground metal tank. These stations were usually in remote places, often in the middle of farmers' fields. Traces of Second World War D/F stations can be seen as circles in the fields surrounding the village of Goonhavern in Cornwall.
Mobile transmitter hunts are organized events where participants travel exclusively or primarily in motor vehicles. Most mobile transmitter hunts use VHF transmitters and receivers. Some participants use radio direction finding equipment and antennas mounted on a vehicle, whereas others use antennas that are temporarily deployed in an open window or an opening in the vehicle roof that can be easily rotated by hand while the vehicle is in motion. Other participants employ handheld antennas and radios that can only be used when the vehicle is stationary.
During the Second World War tactical developments became even more closely tied to the development of new weapons and technologies. The war saw the first large-scale tactical use of hydrophones, sonar (or ASDIC) and radar, and the development of new technologies such as high-frequency direction finding (HF/DF). In the North Sea and Atlantic, Germany lacked the strength to challenge the Allies for command of the sea. Instead, German naval strategy relied on commerce raiding using capital ships, armed merchant cruisers, submarines and aircraft.
Captain H. J. Round working for Marconi had been carrying out experiments for the army in France and Hall instructed him to build a direction finding system for the navy. Stations were built along the coast, and by May 1915 the Admiralty was able to track German submarines crossing the North Sea. Some of these stations also acted as 'Y' stations to collect German messages, but a new section was created within Room 40 to plot the positions of ships from the directional reports.
Aware of the danger presented by radio direction finding (RDF), the Kriegsmarine developed various systems to speed up broadcast. The Kurzsignale code system condensed messages into short codes consisting of short sequences for common terms such as "convoy location" so that additional descriptions would not be needed in the message. The resulting Kurzsignal was then encoded with the Enigma machine and subsequently transmitted as rapidly as possible, typically taking about 20 seconds. Typical length of an information or weather signal was about 25 characters.
Arcadia Publishing, 2004. Mare Island even received Royal Navy cruisers and destroyers and four Soviet Navy subs for service. Following the War, MINSY was considered to be one of the primary stations for construction and maintenance of the Navy's Pacific fleet of submarines, having built seventeen submarines and four submarine tenders by the end of hostilities. Before World War II the Navy established Station I at Mare Island as one of four High Frequency Direction Finding (HFDF) stations on the Pacific mainland to track Japanese naval and merchant shipping east of Hawaii.
The two ships had the same beam, Aguila was just longer and her engine was rated as producing 50 more NHP. In the early 1920s Aguila was joined by a pair of slightly longer sister ships, and , completed by Caledon in April 1922 and January 1923. By 1930 Aguila had wireless direction finding equipment, and from 1934 she had an echo sounding device. Up to 1933 Lloyd's Register records no code letters for Aguila, but when the new wireless call signs were introduced for 1934, she was designated GPVD.
The electronic warfare version was apparently capable of simultaneous connections with a large (unknown) number of friendly aircraft including Command and Control platforms. Its primary role was advanced battlefield direction finding and high speed communications jamming, although it had other ELINT and SIGINT capabilities. It used a tall hydraulically operated mast which was normally carried in the horizontal position on the vehicle's rear left side, protected by a brush guard and a weather shield. When the Teampack system was active, the mast could be quickly deployed into the vertical position.
The RWR system is of Indian design, developed by India's DRDO, called Tarang, (Wave in English). It has direction finding capability and is known to have a programmable threat library. The RWR is derived from work done on an earlier system for India's MiG-23BNs known as the Tranquil, which is now superseded by the more advanced Tarang series. Elta EL/M-8222 a self-protection jammer developed by Israel Aircraft Industries is the MKI's standard EW pod, which the Israeli Air Force uses on its F-15s.
Sculpture of a Mesopotamian boat, 2700-2600 BC. Boat with direction finding birds to find land. Model of Mohenjo-Daro seal, 2500-1750 BCE. In the Assyrian and Hellenistic eras, cuneiform texts continued to use (or revive) old place names, giving a perhaps artificial sense of continuity between contemporary events and events of the distant past. For example, Media is referred to as "the land of the Gutians", a people who had been prominent around 2000 BC. Meluhha also appears in these texts, in contexts suggesting that "Meluhha" and "Magan" were kingdoms adjacent to Egypt.
The main armament is a MSI DS30B 30 mm cannon, supplemented by two 0.50 calibre machine guns. The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, Yarra uses three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
The Allies had learned from decrypted German messages that U-boats were operating near Cape Verde, but not their exact locations. The US Navy dispatched Task Group 22.3 to the area, a "Hunter- Killer" group commanded by Captain Daniel V. Gallery. TG 22.3 consisted of escort aircraft carrier and destroyer escorts under Commander Frederick S. Hall: , , , , and . The group sailed from Norfolk, Virginia on 15 May 1944 and began searching for U-boats in the area in late May, using high-frequency direction-finding fixes ("Huff-Duff") and air and surface reconnaissance.
The main armament is a MSI DS30B 30 mm cannon, supplemented by two 0.50 calibre machine guns. The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, Gascoyne uses three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
For purposes of anti radio direction finding, all radio systems and antennas are remotely moved away from the battalion Combat Operations Center, leaving only the operators with an interface behind. This central hub allows exterior units to communicate with battalion assets. With this system established Indirect Fire Agencies, casualty evacuation, resupply and many other vital services can be accomplished. Enabling systems include satellite communications systems and high frequency radios for long range communication, ultra high frequency radios for air communication and very high frequency radios for tactical ground communication.
The mostly sea-based training and operations are undertaken from a purpose built control room next to the old coastguard cottages at Lepe Beach, overlooking the Western Solent and the Beaulieu River. The control room is fully equipped with charts, radio, direction finding equipment and radar. The land based events and training run out of our Gangwarily HQ a few miles in land. The premises are also where we store our vehicles and work is undertaken in the workshop at Gangwarily, complete with pit and full set of tools / parts.
Lady Nelson was built in 1928 by Cammell Laird of Birkenhead, on the Wirral in England, the same builder for all five Lady class liners. Like her sisters Lady Nelson was an oil-burner, with a set of four Cammell Laird steam turbines driving the propeller shafts to her twin screws by single-reduction gearing. She had three passenger decks, and by 1931 she was equipped with a direction finding device. CN introduced the liners which became known as "Lady Boats" for mail, freight and passenger traffic between Canada, Bermuda and the Caribbean.
They would transmit for several minutes and then go off the air, and another station would take over on the same frequency in a "round robin" chain. This was to confuse enemy aircraft who might be navigating using radio direction finding. By law, radio sets manufactured between 1953 and 1963 had these two frequencies marked by the triangle-in-circle ("CD Mark") symbol of Civil Defense. Although the system by which the CONELRAD process was initiated (switching the transmitter on and off) was simple, it was prone to numerous false alarms, especially during lightning storms.
NASA has reported that modern laptops have crashed when Space Shuttle flights passed through the anomaly. In October 2012, the SpaceX CRS-1 Dragon spacecraft attached to the International Space Station experienced a transient problem as it passed through the anomaly. The SAA is believed to have started a series of events leading to the destruction of the Hitomi, Japan's most powerful X-ray observatory. The anomaly transiently disabled a direction- finding mechanism, causing the satellite to rely solely on gyroscopes that were not working properly, after which it spun itself apart.
Radio traffic compromised his ciphers by giving the Allies more messages to work with. Furthermore, replies from the boats enabled the Allies to use direction finding (HF/DF, called "Huff-Duff") to locate a U-boat using its radio, track it and attack it. The over-centralised command structure of BdU and its insistence on micro- managing every aspect of U-boat operations with endless signals provided the Allied navies with enormous intelligence. The enormous "paper chase" [cross- referencing of materials] operations pursued by Allied intelligence agencies was not thought possible by BdU.
Adcock--who was serving as an Army officer in the British Expeditionary Force in wartime France at the time he filed his invention--solved this problem by replacing the loop antennas with symmetrically inter-connected pairs of vertical monopole or dipole antennas of equal length. This created the equivalent of square loops, but without their horizontal members, thus eliminating sensitivity to much of the horizontally polarized distortion. The same principles remain valid today, and the Adcock antenna array and its variants are still used for radio direction finding.
Improved radar and direction-finding equipment improved the Royal Canadian Navy's ability to find and track enemy submarines over the previous classes. Canada originally ordered the construction of 33 frigates in October 1941. The design was too big for the shipyards on the Great Lakes so all the frigates built in Canada were built in dockyards along the west coast or along the St. Lawrence River. In all Canada ordered the construction of 60 frigates including ten for the Royal Navy that transferred two to the United States Navy.
Between 1940 and 1941, Alexander held the rank of Captain in the Naval Intelligence Service, working on radio direction-finding at Singapore Naval Base. On 4 January 1942, under Navy orders to take her children to safety and return with specialist equipment being made in Australia, Dr. Alexander and her children were evacuated to New Zealand by a Short S23 C flying boat. After the Fall of Singapore on 15 February, she was stranded in New Zealand. She had no information about her husband for six months, and then was misinformed that he was dead.
The armament consisted of three defensive MG 15 machine guns. later supplemented by a further three MG 15s and one MG 17 machine gun. The radio communications were standard FuG X(10), Peil G V direction finding and FuBI radio devices. Due to the increase in defensive firepower, the crew numbers increased from four to five. The empty weight of the P-4 increased to 6,775 kg (14,936 lb), and the full takeoff weight increased to 13,500 kg (29,762 lb). The P-5 was powered by the DB601A.
This meant that Freya did not have to use the two-part structure of CH with a floodlight transmission, and could instead send its signal in a more tightly focused beam like a searchlight. This greatly reduced the amount of energy needed to be broadcast, as a much smaller volume was being filled with the transmission. Direction finding was accomplished simply by turning the antenna, which was small enough to make this relatively easy to arrange. Additionally, the higher frequency of the signal allowed higher resolution, which aided operational effectiveness.
Watson-Watt suggested using Bawdsey Manor as a development site after Wilkins noticed it on a Sunday drive while working at Orfordness. In August 1935, Albert Percival Rowe, secretary of the Tizard Committee, coined the term "Radio Direction and Finding" (RDF), deliberately choosing a name that could be confused with "Radio Direction Finding", a term already in widespread use. In a 9 September 1935 memo, Watson-Watt outlined the progress to date. At that time the range was about , so Watson-Watt suggested building a complete network of stations apart along the entire east coast.
The Civil Air Patrol provides emergency services, including search and rescue and disaster relief missions and assisting in humanitarian aid assignments across the state. The CAP also provides Air Force support through conducting light transport, communications support, and low-altitude route surveys. They also offer support on counter-drug missions with the Department of Homeland Security, Customs and Border Protection, etc. The Hawaii Wing performs tsunami and tropical cyclone warning missions on the ground as well as in the air mounting warning sirens on their Cessna's, as well as urban direction finding.
In that year, Marriott publicly complained that navigation cables still had unrealized potential for guiding ships. . Leader cable systems appear to have been made obsolete by the refinement of radio direction finding and the placement of radio beacons (low-power radio transmitters) at strategic locations. Those beacons are analogous to lighthouses, but can be "seen" in all weather, and are used for navigation in the same way as regular lighthouses. The first successful application of these radio beacons as "radio fog signals" were three stations installed near New York in 1921.
During World War 2, two small radio direction-finding stations were located in Steart. They were part of a secret MI6 organisation called The Radio Security Service listening to and locating the communications of German spies and their handlers. These stations intercepted the messages of the Abwehr, the German Secret Intelligence Service, and provided a large volume of high level intelligence throughout the war. In December 1945, in the nearby village of Combwich The Freedom of Steart was conferred upon Captain Louis Varney, the officer in command of the DF Stations.
According to procedures, both horizontal situation indicators (HSI) were set to 283°, but the magnetic localizer course of 300° was not set. A global positioning system (GPS) was used as a back-up. No requests were made for VHF direction finding. From MSL until impact, the flight was carried out in instrument meteorological conditions (IMC) and the flight controlled by automatic stabilization mode, with lateral navigation controlled by the navigator. At 08:10 UTC, the aircraft reached MSL, which is the minimum altitude to Advent and the initial approach altitude.
The machines were operated mainly by Wrens in a section named the Newmanry after its head Max Newman. The "Radio Security Service" was established by MI8 in 1939 to control a network of Direction Finding and intercept stations to locate illicit transmissions coming from German spies in Britain. This service was soon intercepting a network of German Secret Service transmissions across Europe. Successful decryption was achieved at an early stage with the help of codes obtained from the British XX (Double Cross) System that "turned" German agents and used them to misdirect German intelligence.
The main armament is a MSI DS30B 30 mm cannon, supplemented by two 0.50 calibre machine guns. The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, Huon uses three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
The Lincolnshire Poacher was a British powerful shortwave numbers station that transmitted from Cyprus from the mid-1970s to June 2008. The station gained its commonly known name as it uses bars from the English folk song "The Lincolnshire Poacher" as an interval signal. The radio station was believed to be operated by the British Secret Intelligence Service and emanated from the island of Cyprus. Amateur direction finding linked it with the Royal Air Force base at Akrotiri, Cyprus, where several curtain antennas had been identified as being its transmitter.
71–74 In October 1936, Robert Watson Watt's team working for the Air Ministry began work on what would become Chain Home (CH). By 1936 they had moved to the Bawdsey Manor Research Centre (on the North Sea coast) and had already begun plans for deployment of the CH system. Referred to as Range and Direction Finding (RDF), Bawdsey had by this time begun branching out, forming teams to design and build all sorts of radar related devices. An Army Cell from the SEE was attached to the Bawdsey operation.
Mørch's memoirs as the source, and says he refers to the Danish SIGINT organization as 'the Social Democrat's Child'. Under the agreement, the US was to supply the technical equipment, while Denmark would supply the land and staff. In 1999, however, Frank Jensen, the Social Democratic Minister of Justice and former Minister of Research (responsible for Denmark's telecommunications) denied knowledge of ECHELON. When the journalists visited the Sandagergård facility, they saw a Pusher HF/DF system, which is a smaller version of the Wullenweber intercept & direction-finding antenna, and two radomes.
The main armament is a MSI DS30B 30 mm cannon, supplemented by two 0.50 calibre machine guns. The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, Diamantina uses three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
Why this level of protection was not available in 1967 is difficult to understand. Starting in 1965 and continuing until the end of the AGTR program in 1969, two "technical research" SIGINT ships, AGTR-1 Oxford and AGTR-2 Jamestown, sailed up and down the coast of Vietnam, acting as "firemen" to fill gaps in land- based coverage. They also participated in calibrating airborne direction finding. During this time period, the Medal of Honor was bestowed on the captain of the USS Liberty for his leadership following an Israeli attack on his ship.
Thomas Collins was the first mayor of Portage la Prairie. In 1907, Portage was incorporated as a city, and from that point on, managed to keep a gradual rate of growth and development, serving as a regional hub for agriculture, retail, manufacturing and transportation in central Manitoba. During World War II, the Royal Canadian Air Force constructed Canadian Forces Base Portage la Prairie in support of the British Commonwealth Air Training Plan. The station was controlled by the RCAF but used naval personnel as high-frequency direction finding operators.
This last aircraft, which was still relatively intact, gave Allied intelligence officers their first opportunity to try to establish the basis of the Zero's phenomenal performance. A detailed examination of the aircraft established such crucial factors as maximum range and firepower and also highlighted a number of significant weaknesses such as the lack of fuel tank protection, pilot armour, and armoured glass. Equally significant was the discovery that the Japanese were using Swedish-designed cannons and American- designed direction-finding compasses, propellers and machine-guns. The Zero had already begun to look vulnerable.
ROCA is a sport that requires less athletic skill and more technical radio direction finding skills than ARDF. In a ROCA course, the radio transmitters put out very little power, typically 10 to 200 mW, and can be received over only very short distances. Transmitters may identify themselves in Morse code or with voice recordings, and only transmit for ten seconds during every minute of the competition. The transmitters are physically small, and marked with a control card that is no larger than a typical postcard with a unique number identification.
Decoy control cards may be placed in the competition area, as well, to force competitors to locate the actual transmitting devices. Because of the low power and short distances involved, most ROCA competitors walk the entire course, and focus their attention on the radio direction finding tasks rather than navigation. ROCA is not as popular as ARDF, and activity is limited to only active clubs in a few countries. ROCA events can be found today primarily in the San Francisco Bay area of the United States and in the People's Republic of China.
The Radio Security Service evolved from the Illicit Wireless Intercept Organisation (IWIO), which was given the designation MI1g and run by Lt Col. J S Yule. From an office in Broadway, IWIO collaborated with Military Intelligence, Section 5 (MI5) and with the General Post Office (GPO) to set up and control a small network of Direction Finding (DF) and intercept stations, to locate illicit transmissions inside Britain.TNA File WO 5/208 Col Yule also made detailed plans for similar networks in British overseas territories, before IWIO evolved into RSS in September 1939.
The most severe recent floods occurred in 1981. By 1997, a combination of coastal erosion, sea level rise and wave action had made some of the defences distinctly fragile and at risk from failure. As a result, in 2002 the Environment Agency produced the Stolford to Combwich Coastal Defence Strategy Study to examine options for the future. In the early part of World War II Stockland Bristol was chosen by the Radio Security Service (RSS) as the site for two wireless Direction Finding (D/F) stations known as Y-stations.
Nulls have also been used intentionally to prevent an antenna from broadcasting to a certain area. For example, CIII-DT-22, a repeater of Toronto-based Global TV station CIII-DT in Wheatley has a null towards Windsor to protect broadcast rights of American stations in the bordering Detroit area. Radio direction finding (RDF) receivers use special antennas with very narrow, sharp nulls to find the location of transmitters. The antenna is rotated until the received signal is minimum; at that point the antenna's null is pointed along the bearing line to the transmitter.
This information is transmitted back to surface observers. A weather balloon also known as sounding balloon is a balloon (specifically a type of high-altitude balloon) that carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems (such as the satellite-based Global Positioning System, GPS). Balloons meant to stay at a constant altitude for long periods of time are known as transosondes.
The main armament is a MSI DS30B 30 mm cannon, supplemented by two 0.50 calibre machine guns. The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, Norman uses three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
Patterson in 1951 Doreen Patterson Reitsma (December 12, 1927 – April 30, 2000) was the first woman from British Columbia to enter Canada's newly created Postwar Women's Division of the Royal Canadian Navy. She began her basic training on October 2, 1951, at in Cornwallis, Nova Scotia. She was trained as an elite radio intelligence operator for the wireless communications base at HMC NRS Coverdale. Coverdale was located near the city of Moncton, New Brunswick and was part of the Canada-USA Atlantic High Frequency Direction Finding Network responsible for the collection of military intelligence.
The Dowding system relied on a private telephone network forwarding information from the CH stations, Royal Observer Corps (ROC), and pipsqueak radio direction finding (RDF) to a central room where the reports were plotted on a large map. This information was then telephoned to the four regional Group headquarters, who re-created the map covering their area of operations. Details from these maps would then be sent to each Group's Sectors, covering one or two main airbases, and from there to the pilots via radio. This process took time, during which the target aircraft moved.
480 tons of oil were carried, giving a range of at . The ships had a main gun armament of a single QF 4-inch Mk XIX dual-purpose gun, backed up by two twin and two single Oerlikon 20 mm cannon. Anti-submarine armament consisted of a single triple-barrelled Squid anti-submarine mortar with 81 charges backed up by two depth charge throwers and a single depth charge rail, with 15 depth charges carried. Type 272 or Type 277 surface search radar was fitted, as was high- frequency direction finding (HF/DF) gear.
Ditton Park Smith-Rose undertook post-graduate work at Imperial College before joining Siemens Brothers of Woolwich as an assistant engineer in 1915. He joined the National Physical Laboratory (NPL) in 1919. He received his PhD in 1923 and his D.Sc. in 1926. He was superintendent of the radio department at the NPL from 1939 to 1947 after which he was director of the Radio Research Station at Ditton Park from 1948 to 1960 where, according to the NPL, he became a world leader in radio direction-finding.
This low-level collection team typically has four men. Their primary equipment is the AN/PRD-13 SOF SIGINT Manpack System (SSMS), with capabilities including direction-finding capability from 2 MHz to 2 GHz, and monitoring from 1 to 1400 MHz. SOT-As also have the abilities to exploit computer networks, and sophisticated communications systems. The British 18 (UKSF) Signal Regiment provides SIGINT personnel, including from the 264 (SAS) Signals Squadron and SBS Signals Squadron to provide specialist SIGINT, secure communications, and information technology augmentation to operational units.
In contrast to the former decentralized method of employing radio intelligence units, a more efficient policy of centralization was now instituted, and this radical though effective change in procedure was continued up to the end of the war. This centralization was in keeping with the geographic features of the Italian theatre, as well as the more conventional type of warfare carried on there. The long peninsula, bounded on both sides by the sea, reduced the opportunities for local direction-finding operations. In addition, reception was unfavorably influenced by the Apennines and later the Alps.
The TRSSCOMM had the advantage of being able to transmit large quantities of intelligence information very rapidly without giving away the ship's location to hostile direction finding equipment or interfering with incoming signals. But its major disadvantage is that it could only work if the moon was visible and the stabilization system worked properly. The third extended deployment commenced on 22 January 1969 when Private Jose F. Valdez transited to Africa via Recife, Brazil. Private Jose F. Valdez was ordered home later that year to prematurely end her final deployment.
A lighthouse and direction-finding radio were also once active at this site The Cape Race site, active as a coast radio station until 1966, is now home to the Myrick Communications Museum and a radioamateur commemorative station, VO1MCE. A copy of April 1912 station logs (documenting communication between Cape Race and Titanic) appear in the Maritime Museum of the Atlantic in Halifax, Nova Scotia. The Cape Ray (VCR) and Belle Isle (VCM) stations, which played a similar role, served ocean-going liners in the Gulf of St. Lawrence.
Gablingen was used by the U.S. Army as a barracks, housing various elements of the different divisions stationed in the Augsburg area, as well as USASA Field Station Augsburg, a signals intelligence facility. Around 1970, the 3rd Brigade, 1st Infantry Division moved to Goeppingen. The AN/FLR-9 circular "Wullenweber" antenna array, was built at many locations during the cold war for HF/DF direction finding of high priority targets. The worldwide network, known collectively as "Iron Horse", could quickly and accurately locate an HF communications from almost anywhere on the planet.
The RCAF began sending airmen to the OAC in June 1941 for theoretical training in electronics, radio, and radar. The class size was 75 and the course lasted 13 weeks with Professor W. C. Blackwood of the Physics Department in charge. Trainees who passed the course went on to practical training either at No. 31 Range and Direction Finding School or at a similar establishment in the United Kingdom. With the establishment of the air station in July 1941 the Radio Mechanics School became part of No. 4 Wireless School.
Today Haselgrove's equations are widely used in scientific investigations involving radio propagation in slowly varying plasmas, and therefore have found much applicability in exploration and utilization of the Earth's ionosphere. Here they have also been used to represent the radio propagation element of practical systems providing high frequency communication, direction finding and over-the-horizon radar. For a recent broad discussion on ray tracing in the ionosphere see Bennett et al.J. A. Bennett, P. L. Dyson, R. J. Norman, Progress in Radio Ray Tracing in the Ionosphere, The Radio Science Bulletin, September 2004, p. 81.
Peninnis Head as seen from a passing ship During the Second World War (1939–45) a Radio Direction Finding Station (RDF) was built on Peninnis Head. The first hostile enemy action in the islands occurred on 21 August 1940 when aircraft bombed the RDF. The installation was attacked on several occasions and was destroyed just over a year after the first attack. Peninnis Lighthouse was built in 1911 to replace the lighthouse in the centre of the island of St Agnes, which had been in operation since 1680.
On 31 July she made a sonar contact and fired 16 anti- submarine projectiles at what was later concluded to be either whales or a cold water layer in the ocean. She arrived at Narsarssuaq on 1 August 1944. She patrolled up the east coast of Greenland to Cape Pansch, and supplied remote military bases including radio direction finding stations attempting to localize German U-boats and German weather stations in Greenland. On 19 November 1944 Evergreen landed a party of 27 soldiers on the east coast of Greenland to investigate possible enemy activity.
Sir Robert Alexander Watson Watt, KCB, FRS, FRAeS (13 April 1892 – 5 December 1973) was a British pioneer of radio direction finding and radar technology. Watt began his career in radio physics with a job at the Met Office, where he began looking for accurate ways to track thunderstorms using the radio signals given off by lightning. This led to the 1920s development of a system later known as huff-duff. Although well publicized at the time, the system's enormous military potential was not developed until the late 1930s.
Baird's other developments were in fibre- optics, radio direction finding, infrared night viewing and radar. There is discussion about his exact contribution to the development of radar, for his wartime defence projects have never been officially acknowledged by the UK government. According to Malcolm Baird, his son, what is known is that in 1926 Baird filed a patent for a device that formed images from reflected radio waves, a device remarkably similar to radar, and that he was in correspondence with the British government at the time. The radar contribution is in dispute.
An order for Radio silence is generally issued by the military where any radio transmission may reveal troop positions, either audibly from the sound of talking, or by radio direction finding. In extreme scenarios Electronic Silence ('Emissions Control' or EMCON) may also be put into place as a defence against interception.Emissions Control 3 Mission Airforce Technology In the British Army, the imposition and lifting of radio silence will be given in orders or ordered by control using 'Battle Code' (BATCO). Control is the only authority to impose or lift radio silence either fully or selectively.
The joint American, Italian, and NATO facility houses an AN/FRT-95A Low Frequency Radio Transmitting System, hosts a USAF HF SCOPE Command, part of the High Frequency (HF) Global Communications System (HFGCS) and a US Navy MUOS Ground Station. The surrounding antenna field supports one 827 foot LF antenna, 44 HF (3–30 MHz) antennas, three MUOS Earth Terminal parabolic antennas, and 2 UHF Directional Helical antennas for satellite direction finding. Several different types of HF antenna are installed, though the majority are no longer in use. 116 Antenna towers are installed which hold aloft 35 antenna transmission lines.
Perhaps the most successful NELIAC application was control of the U.S. Navy automated High Frequency Direction Finding network (Classic Bullseye) which went into production in 1968 and lasted until the early 1990s. In addition, NEL developed NELOS, a batch operating system which provided input-output for magnetic tapes, printers, and telecom equipment, provided sequenced compiling of jobs, and a symbol library permitting linking of very large computer applications and executing them on-line. These included suites of information management programs, including databases, free form queries with a precursor of IBM's GIS, and reporting applications. NECPA and NELOS went to sea in 1966.
Higher end beacons such as the Mammut® Pulse Barryvox and Arva® Link are equipped with a digital compass and free- flowing arrow, facilitating more exact direction finding, even rotating to maintain direction between pulses of the transmitting beacon (a feature that is impossible without a digital compass or sophisticated accelerometer). In addition, many higher end beacons can point to victims 360°, including behind the user if the user is moving in the wrong direction. Many digital beacons are also capable of being used in analog mode for more advanced rescuers, or to enhance reception range.
Direction finding could then be carried out with a conventional loop antenna placed in the center of these two stators (or field coils); the rotating loop was known as the rotor (or sense coil). Since the field coils were connected to the antennae electrically, they could be placed anywhere, and their size was independent of the wavelength. This meant that RDF could now be performed on longest wavelengths with ease, using antennae of any size. For longwave use, the two crossed antennae could be easily built by running four wires from a single mast to the ground to form triangular shapes.
Also, the Luftwaffe did not sufficiently appreciate the importance of British Range and Direction Finding (RDF) stations as part of RAF's air defense capability, contributing to their failure. While the United Kingdom and Germany led in pre-war advances in the use of radio for detection and tracking of aircraft, there were also developments in the United States, the Soviet Union, and Japan. Wartime systems in all of these nations will be summarized. The acronym RADAR (for RAdio Detection And Ranging) was coined by the U.S. Navy in 1940, and the subsequent name "radar" was soon widely used.
The vessel's main armament is a MSI DS30B 30 mm cannon, which is supplemented by two 0.50 calibre machine guns. Its sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a GEC-Marconi Type 2093M variable-depth minehunting sonar, an AWADI PRISM radar warning and direction-finding system, and a Radamec 1400N surveillance system. Two Wallop Super Barricade decoy launchers are also fitted. For minehunting operations, Hawkesbury uses three Riva Calzoni azimuth thrusters to provide a maximum speed of : two are located at the stern, while the third is sited behind the variable-depth sonar.
To avoid another disaster like PQ 17, the Admiralty was planning to provide far more support for PQ 18, which included the party on Spitzbergen. Glen was to be the British liaison officer with the Norwegians and Operation Gearbox II was to begin by using the convoy as cover. Bonham- Carter with the cruisers and escorted by and four more destroyers, was to carry the Gearbox II party and about of stores. The delivery included forty Husky sled dogs, three Bofors 40 mm anti-aircraft guns, two tractors, boats, more wireless equipment, including direction finding apparatus and supplies for the winter.
This was followed by thirty-two 5-figure message groups with a morse end of message terminator containing AR 50385 KLK from PTX. (PTX) Up until that point, the Nazi counter- intelligence operation didn't believe that there was a Soviet network operating in Germany and the occupied territories. By September 1941, over 250 messages had been intercepted by the Funkabwehr, but it took several months for them to reduce the suspected area of transmission to within the Belgium area. On 30 November 1941, close range direction-finding teams moved into Brussels and almost immediately found three transmitter signals.
The U.S. Coast Guard searched for a suitable site for a radio direction finding (RDF) site in the Julianehaab area in July 1941, to serve as an auxiliary for sea traffic and anticipated air traffic associated with the BW-1 base which began construction that month. Coast Guard documents show the ship Algonquin arriving from Boston with a radio beacon for Site A (Gamatron) in November. The cutter North Star searched for a construction site and transported men and equipment there. Construction of Gamatron and Simiutak was carried out simultaneously in November and December 1941 and expanded as needed thereafter.
Kolchuga is an electronic support measures system that employs two or more sites to locate emitters by triangulation. The system is vehicle mounted and comprises a large vertical meshed reflector, with two smaller circular parabolic dishes beneath and a pair of VHF-to-microwave log periodic antennas above. The dishes may exploit amplitude monopulse techniques for improved direction finding, whilst the angled spacing of the log-periodic antenna suggests that they may use phase interferometry to improve angle measurements. Various smaller antennas, presumably for inter-site communications are to the side and rear of the dish.
These supplied current to her -high electric propulsion motors, which had a combined rating of 2,833 NHP or 17,000 shp. The turbo-generators and propulsion motors were built by General Electric, which was the world pioneer of turbo-electric propulsion, having supplied the turbo-generators and electric motors for , the World's first turbo-electric ship, a decade earlier. California was equipped with submarine signalling apparatus and wireless direction finding equipment, and from about 1934 she was equipped with a gyrocompass. Californias first class accommodation was air conditioned and some first class cabins had en suite bathrooms.
The captain of the Delphy was also acting as the squadron's navigator, overriding his ship's navigator, Lieutenant (junior grade) Lawrence Blodgett. The Delphy did have radio direction finding (RDF) equipment, which picked up signals from a station at Point Arguello, but RDF was new and the bearings obtained were dismissed by Hunter as unreliable. Based solely on dead reckoning, Captain Watson ordered the fleet to turn east into the Santa Barbara Channel. However, the Delphy was actually several miles northeast of where they thought they were, and the error caused the ships to run aground on Honda Point.
This is especially the case of the coast lines of the Indus and Mesopotamia, which were originally only separated by a distance of about 1000 kilometers, compared to 2000 kilometers today. For the ancestors of the Sumerians, the distance between the coasts of the Mesopotamian area and the Indus area would have been much shorter than it is today. In particular the Persian Gulf, which is only about 30 meters deep today, would have been at least partially dry, and would have formed an extension of the Mesopotamian basin. Sea-going vessel with direction finding birds to find land.
Nations that have participated in major international competitions since the first European Championship in 1961 The sport originated in Northern Europe and Eastern Europe in the late 1950s. Amateur radio was widely promoted in the schools of Northern and Eastern Europe as a modern scientific and technical activity. Most medium to large cities hosted one or more amateur radio clubs at which members could congregate and learn about the technology and operation of radio equipment. One of the activities that schools and radio clubs promoted was radio direction finding, an activity that had important civil defense applications during the Cold War.
It was believed by US intelligence that COSVN had several subdivisions, each of which dealt with the political, logistical, and military aspects of the struggle in South Vietnam. For tactical reasons US Radio Research units were primarily concerned with the military divisions, which were known as "MAS-COSVN" (Military Affairs Section) and "MIS-COSVN" (Military Intelligence Section). The political and logistical sub-divisions were left to the 175th Radio Research Field Station at Bien Hoa. These two sub-divisions usually occupied a location removed from, but generally near, the headquarters itself, as determined by ARDF or airborne radio direction finding.
Sink the Bismarck! was made before 1975, when the British code-breaking at Bletchley Park was declassified, so it did not reveal that Shepard's hunches about the movements of the Bismarck were supported by intelligence. Direction finding and traffic analysis showed that on 25 May, Bismarck stopped talking to Wilhelmshaven and started up with Paris, and Shepard committed to the belief that Bismarck was headed for the French coast. The radio switch from Wilhelmshaven to Paris might have been caused by Bismarcks crossing the line southern Greenland – northern Hebrides which brought her under Group West instead of Group North.
Fragmentation of groups, the need for secrecy, and emerging conflicts between right and left, monarchists and republicans, did not help. Urban resistance work was very dangerous: operatives were always in danger of arrest and summary execution, and suffered heavy casualties. Captured fighters were routinely tortured by the Abwehr and the Gestapo, and confessions used to roll up networks. The job of wireless operators was perhaps the most dangerous, since the Germans used direction-finding equipment to pinpoint the location of transmitters; operators were often shot on the spot, and those were the lucky ones, since immediate execution prevented torture.
The Chinese Radio Sports And Orienteering Association (CRSAOA) (in simplified Chinese, 中国无线电和定向运动协会) is a national non-profit organization for amateur radio enthusiasts in the People's Republic of China. The CRSA's primary mission is to popularize and promote amateur radio in China. Early activities of the organization focused on radiosport, and the CRSA was active in promoting Amateur Radio Direction Finding and High Speed Telegraphy competitions throughout the country. Although the CRSA has broadened its scope and now supports many kinds of radio activities, the organization's name continues to reflect this early heritage.
Similarly, he was the only person to receive accurate charts of German minefields prepared from Room 40 information. No attempts were made by the German fleet to restrict its use of wireless until 1917, and then only in response to perceived British use of direction finding, not because it believed messages were being decoded. It became increasingly clear, that as important as the decrypts were, it was of equal importance to accurately analyse the information provided. An illustration of this was provided by someone at the Admiralty who knew a little too much detail about SIGINT without fully understanding it.
Radio direction finding was a widely used technique even before World War I, used for both naval and aerial navigation. The basic concept used a loop antenna, in its most basic form simply a circular loop of wire with a circumference decided by the frequency range of the signals to be detected. When the loop is aligned at right angles to the signal, the signal in the two halves of the loop cancels out, producing a sudden drop in output known as a "null". Early DF systems used a loop antenna that could be mechanically rotated.
In 1941, one of the 4.7 in guns and the aft bank of torpedo tubes was removed, with a anti-aircraft gun replacing the torpedo tubes and an enhanced anti-submarine armament, which included 70 depth charges and the ability to drop patterns of 10 charges. Radar was also fitted, and the destroyer's close-in anti-aircraft outfit was supplemented by the addition of Oerlikon 20 mm cannons, of which two were fitted in 1941 followed by four more later on. The 3 inch gun was removed by 1943, when high-frequency direction finding gear was fitted.
Two quadruple mounts for 21 inch (533 mm) torpedoes were fitted, while the ship had an depth charge outfit of four depth charge mortars and two racks, with a total of 70 charges carried. Troubridge was fitted with a Type 291 air warning radar on the ship's tripod foremast, with a Type 285 fire control radar integrated with the ship's high-angle gun director. A high-frequency direction finding (HF/DF) aerial was fitted to a lattice mainmast. Troubridge was fitted as a leader, and as such had a crew of 225 officers and other ranks.
Even if Itasca could get a bearing to the plane, the Itasca could not tell the plane that bearing, so the plane could not head to the ship. Some sources have noted Earhart's apparent lack of understanding of her direction-finding system, which had been fitted to the aircraft just prior to the flight. The system was equipped with a new receiver from Bendix that operated on five wavelength "bands", marked 1 to 5. The loop antenna was equipped with a tuneable loading coil that changed the effective length of the antenna to allow it to work efficiently at different wavelengths.
During Earhart and Noonan's approach to Howland Island, the Itasca received strong and clear voice transmissions from Earhart identifying as KHAQQ but she apparently was unable to hear voice transmissions from the ship. Signals from the ship would also be used for direction finding, implying that the aircraft's direction finder was also not functional. The first calls, routine reports stating the weather as cloudy and overcast, were received at 2:45 and just before 5 am on July 2. These calls were broken up by static, but at this point the aircraft would still be a long distance from Howland.
In the 1940 film, Flight Command, a defect in a piece of direction-finding gear is called a "bug". In a book published in 1942, Louise Dickinson Rich, speaking of a powered ice cutting machine, said, "Ice sawing was suspended until the creator could be brought in to take the bugs out of his darling." Isaac Asimov used the term "bug" to relate to issues with a robot in his short story "Catch That Rabbit", published in 1944. A page from the Harvard Mark II electromechanical computer's log, featuring a dead moth that was removed from the device.
South-pointing chariot replica at the Ibn Battuta Mall, Dubai Some non-mechanical method of finding the south must have been used when a mechanical south-pointing chariot was initialized, aiming its pointer to the south at the start of a journey. Any of the methods mentioned above in "Non-mechanical possibilities" could have been used. If any south-pointing chariot was really used for long-distance navigation, it must have relied (after initialization) on a non-mechanical direction-finding method. It might have been operated non-mechanically by someone riding in it, as outlined above.
Due to relatively low purchase, maintenance and calibration cost, NDB's are still used to mark locations of smaller aerodromes and important helicopter landing sites. Similar beacons located in coastal areas are also used for maritime radio navigation, as almost every ship is (was) equipped with a direction finder (Appleyard 1988). Very few maritime radio navigation beacons remain active today (2008) as ships have abandoned navigation via RDF in favor of GPS navigation. In the United Kingdom a radio direction finding service is available on 121.5 MHz and 243.0 MHz to aircraft pilots who are in distress or are experiencing difficulties.
British Post Office RDF lorry from 1927 for finding unlicensed amateur radio transmitters. It was also used to find regenerative receivers which radiated interfering signals due to feedback, a big problem at the time. In World War II considerable effort was expended on identifying secret transmitters in the United Kingdom (UK) by direction finding. The work was undertaken by the Radio Security Service (RSS also MI8). Initially three U Adcock HF DF stations were set up in 1939 by the General Post Office. With the declaration of war, MI5 and RSS developed this into a larger network.
A dipole antenna exhibits similar properties, and is the basis for the Yagi antenna, which is familiar as the common VHF or UHF television aerial. For much higher frequencies still, parabolic antennas can be used, which are highly directional, focusing received signals from a very narrow angle to a receiving element at the centre. More sophisticated techniques such as phased arrays are generally used for highly accurate direction finding systems called goniometers such as are used in signals intelligence (SIGINT). A helicopter based DF system was designed by ESL Incorporated for the U.S. Government as early as 1972.
Improved radar and direction-finding equipment improved the RCN's ability to find and track enemy submarines over the previous classes. Canada originally ordered the construction of 33 frigates in October 1941. The design was too big for the locks on the Lachine Canal so it was not built by the shipyards on the Great Lakes and therefore all the frigates built in Canada were built in dockyards along the West Coast or along the St. Lawrence River below Montreal. In all Canada ordered the construction of 60 frigates including ten for the Royal Navy that transferred two to the United States Navy.
I can be suggested that since the material after the redactions spoke of traffic analysis as more general, the redacted sections dealt with message content interception, cryptanalysis, and translation. While the methods were not yet called MASINT, there was a Special Identification Techniques (SIT) facility at the ASA site at Clark AFB could use to do "radio fingerprinting" to recognize unique Morse code operator "fists". This revealed little, and the problem was traced to inadequate direction finding. After deletions, it is observed that NSA concluded it needed another 105 intercept stations, giving over 2400 hours of coverage.
Since the Vietnam War, for example, had been declared off-limits by French censors, Charlier wrote the "Return of the Flying Tigers" story arc to take place in the fictional country of Vien-tan. The realism of the series is also enhanced by short definitions or explanations of technical terms, such as radar or Radio direction finding. For this the authors often use separate texts, diagrams, drawings and schemes. Novels also often contain technical or historical notes, and at other times, English aviator jargon (such as "Scramble" or "Overshoot") is translated into French for the readers' benefit.
The United States Navy apparently did not want to acknowledge Japanese submarine activity off the Pacific Coast during the Second Happy Time and officially attributed the sinking of Coast Trader to "an internal explosion."Webber, Bert, Retaliation: Japanese Attacks and Allied Countermeasures on the Pacific Coast in World War II, Oregon State University Press, 1975, pp. 18-19 In the evening of 20 June 1942, while patrolling two miles off the coast of British Columbia, I-26 surfaced and shelled the lighthouse and radio-direction-finding (RDF) installation at Estevan Point.Historylink.org, Japanese submarine sinks the SS Coast Trader on June 7, 1942.
In August of that year he was awarded the Air Force Cross (AFC) for meritorious flying as an experimental pilot at Farnborough; he had flow into a barrage balloon cable to test a newly invented protective device. During this tour, he also carried out development work testing wireless direction finding, radio control; he experimented personally with early types of parachute. In recognition, he was awarded a Bar to his AFC in 1921. At the Hendon Pageant of 1922, he demonstrated the manoeuvrability of the D.H.10 twin-engined bomber in a mock dogfight with S.E 5 fighters.
The system is not Global Maritime Distress & Safety System-compatible, coverage gaps exist in several locations, it cannot operate on public safety channels, it has no direction finding capability, distress calls cannot be received at a high site when the site is transmitting on any channel, and the system is near the end of its useful life. For these reasons, the Coast Guard began to modernize this system in 2003. The National Distress System is operated by 45 Coast Guard Group and Section Command Centers, each acting as a Maritime Rescue Coordination Center having a specific area of responsibility.
MOD Website - HMS Collingwood HMS Collingwood gained its name from Lord Collingwood, a distinguished admiral at the turn of the 19th century. The current shore establishment was commissioned as the fourth HMS Collingwood on 10 January 1940, initially to instruct "hostilities only" ratings of the seaman branch. Wireless telegraphy ratings started their training in June 1940, and a radio direction finding school was added in 1942. In 1946 Collingwood took over the training of both officers and ratings in the maintenance of all electrical and radio equipment in the fleet, except that of the Fleet Air Arm.
The Lancaster had a very advanced communications system for its time. Most British-built Lancasters were fitted with the R1155 receiver and T1154 transmitter, whereas the Canadian-built aircraft and those built for service in the Far East had American radios. These provided radio direction-finding, as well as voice and Morse capabilities. ; H2S : 3 GHz frequency, ground-looking navigation radar system – eventually, it could be homed in on by the German night fighters' FuG 350 Naxos receiver and had to be used with discretion – a problem which the higher resolution, 10 GHz frequency American H2X radar never had to deal with.
Chicksands is mentioned in the Domesday Book the entry reads: Chichesana/e: William de Cairon from Bishop of Lincoln; Three freemen and Walter from Azelina, Ralph Tailbois' wife (it is of her dowry). Mill. Chicksands was the site of RAF Chicksands, an RAF station during World War II. The station was used by the United States Air Force from 1950 to 1995. It was the location for its first huge FLR-9 direction finding antenna from 1963 to 1995. The antenna was known as the 'Elephant Cage' and was dismantled before the USAF left in 1995.
Work on a high speed machine had been started by Wynn-Williams of the TRE late in 1941 and some nine months later Harold Keen of BTM started work independently. Early in 1942, Bletchley Park were a long way from possessing a high speed machine of any sort. Eventually, after a long period of being unable to decipher U-boat messages, a source of cribs was found. This was the Kurzsignale (short signals), a code which the German navy used to minimize the duration of transmissions, thereby reducing the risk of being located by high-frequency direction finding techniques.
The Action off Lerwick (, "Lerrick") was a naval engagement on 17 October 1917 fought in the North Sea during the First World War. The German light, minelaying cruisers and attacked a westbound convoy of twelve colliers and their escorts. The two escorting destroyers and nine neutral Scandinavian ships were sunk off Shetland, Scotland. Admiralty code breakers had uncovered the call signs of Bremse and Brummer and by direction finding knew that they had sailed from Wilhelmshaven to Lister Tief (Lister Deep) north of Sylt but an operation as far north as the Scandinavian collier route was not anticipated.
Improved radar and direction-finding equipment improved the RCN's ability to find and track enemy submarines over the previous classes. Canada originally ordered the construction of 33 frigates in October 1941. The design was too big for the locks on the Lachine Canal so it was not built by the shipyards on the Great Lakes and therefore all the frigates built in Canada were built in dockyards along the West Coast or along the St. Lawrence River below Montreal. In all Canada ordered the construction of 60 frigates including ten for the Royal Navy that transferred two to the United States Navy.
An antenna array can achieve higher gain (directivity), that is a narrower beam of radio waves, than could be achieved by a single element. In general, the larger the number of individual antenna elements used, the higher the gain and the narrower the beam. Some antenna arrays (such as military phased array radars) are composed of thousands of individual antennas. Arrays can be used to achieve higher gain, to give path diversity (also called MIMO) which increases communication reliability, to cancel interference from specific directions, to steer the radio beam electronically to point in different directions, and for radio direction finding (RDF).
Transmitter hunting is pursued in several different popular formats. Many transmitter hunts are organized by local radio clubs, and may be conducted in conjunction with other events, such as a radio enthusiast convention or club meeting. Before each hunt, participants are informed of the frequency or frequencies on which the transmitters will be operating, and a set of boundaries that define a search area in which the transmitters will be located. Transmitter hunters use radio direction finding techniques to determine the likely direction and distance to the hidden transmitter from several different locations, and then triangulate the probable location of the transmitter.
The results were such that, "Canadian...intercept stations and Direction Finding (DF) organizations...made an indispensable contribution to the Allied North Atlantic SIGINT network." The Intelligence Staffs of both the First and Second Canadian Infantry Divisions in England and other newly inducted C Int C personnel in theatre, continued to be sent to British Intelligence Schools for advanced training. On conclusion of their courses, they were attached to the Intelligence staffs of some of the more experienced British formations, while British Intelligence officers filled their places in the Canadian Army temporarily. As the Canadians became more proficient, they gradually replaced their British colleagues.
136 From the mediaeval era until the 19th century Weaverthorpe was part of the Wapentake of Buckrose. Between 1894 and 1974 it was a part of the East Riding of Yorkshire, firstly in the Driffield Rural District, then moving to the Norton Rural District in 1935. Since 1974 it has been in the Ryedale district of North Yorkshire. During the Second World War, MI6 secretly installed a new type of direction finding station in a field just south of the village, it consisted of an underground metal tank with an aerial protruding above rotated by the operator inside the tank.
A pair of octuple mounts for 2-pounder () Mk VIII "pom-pom"s were added on platforms abreast the funnel and directors for them were fitted on the foremast. A pair of quadruple mounts for Vickers AA machineguns were added abreast the conning tower and the mainmast was reconstructed as a tripod to support the weight of the second HACS. In addition the aft torpedo tubes were removed. By June 1938 the single mounts of the AA guns were replaced by twin mounts, the forward torpedo tubes were removed, a radio-direction finding office was added and the catapult was removed.
A review posted on the U.S. Naval Cryptologic Veterans Association website addresses the intelligence issues in greater detail and disputes claims that the fleet was detected through direction finding; the author also criticizes Stinnett's use of testimony from Robert Ogg, originally identified as "Seaman Z" by John Toland in his 1986 book. Indeed, Ogg expressly denies saying what Toland quotes him as saying.Young, p.8. In their annotations on the 1995 Pentagon study of the attack, Frederic Borch and Daniel Martinez, chief historian at the USS Arizona Memorial, also dispute these claims and call his claims "totally false".
The Slovenský Zväz Rádioamatérov (SZR) (in English, Slovak Amateur Radio Association) is a national non-profit organization for amateur radio enthusiasts in Slovakia. Key membership benefits of the SZR include the sponsorship of amateur radio operating awards, radio contests, and a QSL bureau for members who regularly communicate with amateur radio operators in other countries. SZR represents the interests of Slovakian amateur radio operators before Slovak Republic and international telecommunications regulatory authorities. SZR also supports local competitions in Amateur Radio Direction Finding as well as a national team that travels to regional and world championship events.
Sonar was not included, but there was more attention given to recognition (IFF), direction-finding, and LORAN radio-navigation systems. There were also special courses on subjects such as the Norden bombsight, the magnetic anomaly detector (MAD), and the Target Drone Denny (TDD-1). One of the laboratories was in a hangar that contained several aircraft for ground-testing of electronic equipment. NATTC Ward Island also had a small fleet of aircraft of various types that operated from nearby NAS Corpus Christi; every student was required to have flight time in operating the on-board equipment.
Unfortunately for the German plan, the British had obtained a copy of the main German codebook from the light cruiser , which had been boarded by the Russian Navy after the ship ran aground in Russian territorial waters in 1914. German naval radio communications could therefore often be quickly deciphered, and the British Admiralty usually knew about German activities. The British Admiralty's Room 40 maintained direction finding and interception of German naval signals. It had intercepted and decrypted a German signal on 28 May that provided "ample evidence that the German fleet was stirring in the North Sea".
In the 1940 film, Flight Command, a defect in a piece of direction-finding gear is called a "bug". In a book published in 1942, Louise Dickinson Rich, speaking of a powered ice cutting machine, said, "Ice sawing was suspended until the creator could be brought in to take the bugs out of his darling." Isaac Asimov used the term "bug" to relate to issues with a robot in his short story "Catch That Rabbit", published in 1944. A page from the Harvard Mark II electromechanical computer's log, featuring a dead moth that was removed from the device.
The Italian prisoners were transferred to the oiler Pearleaf with an armed guard of nineteen ratings and an officer; the ship made for Colombo, Ceylon (now Sri Lanka). Leander was sent to investigate wireless direction-finding indications that Axis ships were in the vicinity of the Saya de Malha Bank, several hundred miles south- east of the Seychelles Islands and north-east of Madagascar. Coburg with a prize, Ketty Brovig, a Norwegian tanker, was spotted south-east of the Seychelles by a spotter aircraft from and both ships were scuttled when Canberra and Leander approached them.
In 1783, several hundred members of The Religious Society of Friends moved from the newly founded United States of America to Pennfield as a result of The American Revolution. During the summer of 1940, an airport was constructed to train Air Observes as part of the British Commonwealth Air Training Plan. An Operational Training Unit was used at the airport to train the four members of the crew for World War II action: Pilot, Navigator, Wireless Air Gunner and Air Gunner. The Royal Canadian Air Force allowed the Royal Canadian Navy to use their equipment for High Frequency Direction Finding activities against German submarines in the Atlantic.
Newer techniques of VHF radio communications and direction-finding might also be used, but all of these methods were highly vulnerable to enemy interception. At the NTRI, Yoji Ito proposed that the UHF signal from a magnetron might be used to generate a very narrow beam that would have a greatly reduced chance of enemy detection. Development of microwave system for collision avoidance started in 1939, when funding was provided by the Imperial Navy to JRC for preliminary experiments. In a cooperative effort involving Yoji Ito of the NTRI and Shigeru Nakajima of JRC, an apparatus using a 3-cm (10-GHz) magnetron with frequency modulation was designed and built.
Increment 2, the first upgrade program, was implemented in 2005 for Block 20 aircraft onward and enabled the employment of Joint Direct Attack Munitions (JDAM). Certification of the improved AN/APG-77(V)1 radar was completed in March 2007, and airframes from production Lot 5 onward were fitted with this radar, which incorporates air-to-ground modes.AP/APG-77(V). Forecast International. March 2012 Increment 3.1 for Block 30 aircraft onward provided improved ground-attack capability through synthetic aperture radar mapping and radio emitter direction finding, electronic attack and Small Diameter Bomb (SDB) integration; testing began in 2009 and the first upgraded aircraft was delivered in 2011.
50 inch Vickers machine gun mount and two Oerlikon 20 mm cannon in 1941, together with a single 2-pounder (40-mm) "pom-pom", with the machine guns removed to allow a further four Oerlikon cannon to be fitted in 1942. Anti-submarine armament gradually increased throughout the ship's career. The number of depth charges carried increased first to 40, matching that carried by the last two ships of the Grimsby-class, and later to 60.. A Hedgehog anti-submarine mortar was fitted in 1943. Type 286 radar was fitted during 1941, later supplemented by Type 271 and Type 291, while HF/DF radio direction-finding gear was also fitted.
The control car was well forward on the ship, with the aft section containing an engine in a separate structure to stop vibrations affecting the sensitive radio direction finding and communication equipment. The small gap was faired over, so the gondola seemed to be a single structure.Higham 1961, p.181 It was powered by five Sunbeam Maori engines, with one in the aft section of the control car, two more in a pair of power cars amidships each driving a pusher propeller via a reversing gearbox for manoeuvering while mooring, and the remaining two in a centrally mounted aft car, geared together to drive a single pusher propeller.
A Maritime Survivor Locator Device (MSLD) is a man-overboard locator beacon. In the U.S., rules were established in 2016 in 47 C.F.R. Part 95 MOB devices with DSC or AIS are allocated MMSI numbers in the range 972yyzzzz. A MSLD may transmit on 121.500 MHz, or one of these: 156.525 MHz, 156.750 MHz, 156.800 MHz, 156.850 MHz, 161.975 MHz, 162.025 MHz (bold are Canadian-required frequencies). Although sometimes defined in the same standards as the COSPAS-SARSAT beacons, MSLDs can not be detected by that satellite network, and are instead intended only for short-range Direction finding equipment mounted on the vessel on which the survivor was traveling.
"IARU Region 1 Record of Participation in Regional and World Amateur Radio Direction Finding Championships.". Retrieved October 20, 2005. A member of the Republic of Korea national team sprints to the finish line of an eighty meter ARDF course. As the sport grew in the 1960s and 1970s, each nation devised its own set of rules and regulations. The need for more clearly defined and consistent rules for international competitions led to the formation of an ARDF working group by the International Amateur Radio Union (IARU) in the late 1970s. The first ARDF event to use the new standardized rules was the 1980 World Championship.
To increase the magnetic field in the loop and thus its efficiency, while greatly reducing size, the coil of wire is often wound around a ferrite rod magnetic core; this is called a ferrite loop antenna. Such ferrite loop antennas are used in almost all AM broadcast receivers with the exception of car radios; the antenna is then usually contained inside the radio's chassis. These antennas are also used for radio direction finding. LF, MF, and HF spectrum according CCIR 322 The radiation resistance of a small loop is generally much smaller than the loss resistance due to the conductors composing the loop, leading to a poor antenna efficiency.
The EH-60L has better communications and ungradability than the A model, with the AN/MSR-3 TACJAM-A system. RC-12 Guardrail aircraft provide a corps-level ESM capability, with the unusual approach of putting all the analysis equipment on the ground, with the RC-12K/N/P/Q aircraft acting purely as intercept and relay platforms. The Guardrail aircraft normally fly in units of three, to get better cross- bearings in direction-finding. The Navy EA-6B Prowler replaced the USAF EF-111 Raven EW aircraft for all services, and the EA-6B Prowler is being replaced by the EA-18G Growler.
Pennsylvania was the last of three sister ships built by the Newport News Shipbuilding and Drydock Company of Newport News, Virginia for the American Line Steamship Corporation, which at the time was part of J. P. Morgan's International Mercantile Marine Co. Pennsylvania was launched on 10 October 1929. She joined () and SS Virginia () in the fleet of American Lines' Panama Pacific Lines subsidiary. Pennsylvania was a steamship, with oil-fired furnaces heating her boilers to power two General Electric steam turbo generators supplying current for her electric propulsion motors. Pennsylvania was equipped with submarine signalling apparatus and wireless direction finding equipment, and from about 1934 she was equipped with a gyrocompass.
The expedient solution to this was the use of huff-duff stations to tune in on the fighter's radios. Every Sector Control, in charge of a selection of fighter squadrons, was equipped with a huff-duff receiver, along with two other sub-stations located at distant points, about away. These stations would listen for broadcasts from the fighters, compare the angles to triangulate their location, and then relay that information to the control rooms."High-frequency direction finding" Comparing the positions of the enemy reported by the ROC and the fighters from the huff-duff systems, the Sector Commanders could easily direct the fighters to intercept the enemy.
Ceramics maiden voyage began on 24 July 1913 when she left Liverpool for Australia. At the time she was the largest liner on the route between the two countries. In 1914 she was requisitioned for the First Australian Imperial Force as the troopship HMAT (His Majesty's Australian Transport) Ceramic, with the pennant number A40. She was armed with two stern-mounted QF 4.7 inch (120mm) naval guns. By 1933 she carried wireless direction finding and echo sounding equipment. In 1916 Ceramic took the Territorial Army 25th (County of London) Cyclist Battalion to India, leaving Devonport on 3 February and reaching Bombay on 25 February.
The rescue ships were not hospital ships and so were legitimate targets as far as German submarines or bombers were concerned. Consequently, the Admiralty armed them with AA guns for protection when they were separated from the convoy and vulnerable to enemy attack. In addition to equipment for rescuing and treating survivors, rescue ships carried High Frequency radio Direction Finding equipment (abbreviated to HF/DF and known as "Huff-Duff") to assist in the location of U-boats. The rescue ship's position at the rear of the convoy provided good triangulation in combination with the HF/DF installed on the escort leader typically patrolling in front of the convoy.
Bégué had an exhausting schedule, often transmitting and receiving messages to and from SOE three times a day. In addition he often had to serve as a courier traveling by train to deliver or receive messages to other SOE agents. As the Germans and French police were attempting to locate him and his wireless through direction-finding equipment, Bégué proposed sending seemingly obscure personal messages to agents in the field in order to reduce risky radio traffic. In accordance with his proposal, the BBC's Radio Londres broadcasts began with "Please listen to some personal messages," followed by spoken messages, often amusing, and without context.
In May 1943, Viscount returned to North Atlantic convoy duty. While escorting Convoy ONS 6 with the 6th Escort Group on 8 May 1943, she got a radio direction-finding fix on a German submarine and closed with it, sighting it at a range of . The submarine submerged, and Viscount attacked it with depth charges, but without success. Over the course of the summer of 1943, Viscount was detached for Operation Derange, consisting of offensive antisubmarine operations in the Bay of Biscay in which aircraft and ships cooperated in attacks on German submarines transiting the bay between their bases in German-occupied France and the Atlantic shipping routes.
The Bellini–Tosi direction finder was a type of radio direction finder that was widely used from World War I to World War II. It used the signals from two crossed antennas, or four individual antennas simulating two crossed ones, to re- create the radio signal in a small area between two loops of wire. The operator could then measure the angle to the target radio source by performing direction finding within this small area. The advantage to the Bellini–Tosi system is that the antennas do not move, allowing them to be built at any required size. The basic technique remains in use, although the equipment has changed dramatically.
Two quadruple mounts for 21 inch (533 mm) torpedoes were fitted, while the ship had an depth charge outfit of four depth charge mortars and two racks, with a total of 70 charges carried. Whirlwind was fitted with a Type 276 surface warning radar on the ship's lattice foremast, together with a high-frequency direction finding (HF/DF) aerial, with a Type 291 air warning radar on a pole mast aft. A Type 285 fire control radar integrated with the ship's high-angle gun director, while the Hazemayer mount had an integrated Type 282 radar. Whirlwind had a crew of 179 officers and other ranks.
For example, Malaysia and Singapore jointly monitor the South China Sea electronically. It is reasonable to assume that the less sensitive aspects of SIGINT, such as Direction finding are part of that surveillance. Other sources include the Five Power Defence Arrangements (FPDA) of Australia, Great Britain, New Zealand, Singapore and Malaysia, which includes three members of the UKUSA alliance with strong national SIGINT organizations. Spurred by terrorism concerns, the ASEAN states, in May 2002, agreed on an Action Plan that provided for enhanced cooperation in intelligence sharing and coordination of anti-terror laws. In August 2002, ASEAN and the United States issued a “Joint Declaration . . .
Reports of distant areas, like the Caribbean became more common. By Winter 1943–44, and the resumption of an offensive war against Allied convoys (Battle of Atlantic Final Years) brought back convoy messages. With the difficulties of finding convoys to attack, and with the Allies now reading all communications that the Kriegsmarine sent, concurrently, with daily allied operations, new types of intelligence messages including direction finding (Radio direction finder) on positions of Allied units and special reports from intercept parties aboard U-boats became more prominent. Particular concerns included Allied location devices, the positions of U.S. Navy Escort carrier groups (In an attempt to ensure that U-boats surface safely).
Cormeau was a talented and accurate wireless (W/T) operator, being able to transmit 18 to 22 words per minute in Morse code, compared with the 12 words per minute of the average operator. This was important because the longer an operator (called a "pianist" in SOE slang) was on line the more likely the Germans were to find them using direction finding equipment.O'Connor, Bernard (2012), Churchill's Angels, Stroud, Gloucestershire: Amberley Publishing, pp 119-120 The standard wireless transceiver issued to SOE wireless operators was the B Mark II, a cumbersome machine concealed in a suitcase. It required the operator to extend a wire aerial long.
The traffic became a valuable source of intelligence, so the control of RSS was subsequently passed to MI6 who were responsible for secret intelligence originating from outside the UK. The direction finding and interception operation increased in volume and importance until 1945. The HF Adcock stations consisted of four 10m vertical antennas surrounding a small wooden operators hut containing a receiver and a radio-goniometer which was adjusted to obtain the bearing. MF stations were also used which used four guyed 30m lattice tower antennas. In 1941, RSS began experimenting with spaced loop direction finders, developed by the Marconi company and the UK National Physical Laboratories.
Location of radio-tagged animals by triangulation is a widely applied research technique for studying the movement of animals. The technique was first used in the early 1960s, when the technology used in radio transmitters and batteries made them small enough to attach to wild animals, and is now widely deployed for a variety of wildlife studies. Most tracking of wild animals that have been affixed with radio transmitter equipment is done by a field researcher using a handheld radio direction finding device. When the researcher wants to locate a particular animal, the location of the animal can be triangulated by determining the direction to the transmitter from several locations.
The convoy enters the "Black Pit"—the Mid-Atlantic gap where they will be out of range of protective air cover. While they are still three days away from the resumption of air cover, high-frequency direction finding (HUFFDUFF) from the convoy flagship reports to Greyhound that it has intercepted German transmissions that are likely from a U-boat (submarine). Greyhound's crew identifies the surfaced sub heading toward the convoy. Greyhound moves away from the convoy to intercept it based on its bearing and gets the U-boat within firing range, but the heavy seas allow the U-boat to dive before Greyhound can get a visual.
Beekman's steadfast and fearless approach had proved invaluable to the circuit, but her work was becoming riskier every day. German interception of radio signals had become very efficient by this time, and the regular times of her transmissions was helping her pursuers to gradually narrow down the area of the source. Beekman and Bieler spent Christmas Eve at the Bourys' house; they listened to the BBC and did their best to be festive. On Christmas Day she made contact with London as usual, but the following week a direction finding van was seen passing the house, an ominous sign that the net was closing in.
Kurier was a simple system largely consisting of the KZG 44/2, a metal drum with 85 small metal bars that could be pushed into two positions. A message was prepared using the Navy's kurzsignale encoding method that reduced messages to a short series of four-letter codes, and then encrypted using the Naval Enigma machine. Conventional transmission of the kurzsignale at this stage would take about 20 seconds, fast enough to defeat conventional radio direction finding, but not huff-duff. The resulting short message was converted into Morse code and entered onto the KZG 44/2, with dots as a single bar and dashes as two.
The U-boat wolfpacks were under the direct command of GrossAdmiral Karl Dönitz, the German naval commander in chief. A former submariner with service in World War I, Dönitz insisted on personally guiding the submarine war, requiring his submarine captains to report in to him directly, often multiple times per day. A High Frequency Direction Finding system could determine the point of origin of such transmissions; the high level of radio traffic between the U-boat commanders and Dönitz's headquarters would provide the Allies with ample opportunities to use HF/DF to detect the wolfpacks and determine their locations and bearings.Wise, Mark E., and Jak P. Mallmann Showell.
A Mountain Locator Unit or MLU was a radio transmitter for use by mountain climbers as an emergency locator beacon when the wearer needs rescue. The MLUs were simple radio beacons, and thus required search and rescuers to use traditional radio direction finding (RDF or DF) equipment to obtain a bearing, but not a precise location, to the beacon. Unique to Mount Hood, these devices could be rented for $5 at Portland-area outdoor shops and the Inn, open 24 hours a day. The units were available from the late 1980s until 2017, but advances in technology now provide superior locating information by devices such as a PLB, InReach or Spot.
In the early morning of 5 May, following a lengthy hunt, the half-group (the other half were kept with Vindex), were sent to an area known to contain a U-boat which was on weather- reporting duty. With the use of direction-finding equipment and aircraft from Vindex, the search area was reduced. Having found his target, Macintyre then decided to use the 'creeping' attack method pioneered by Captain 'Johnnie' Walker. This involved the use of a second ship, (in this case the frigate HMS Bligh), to do the actual attacking while the first ship (Bickerton), controlled things such as the ASDIC tracking.
She was given a lengthy refit at Halifax in April–August 1942. In early December 1942, the ship's director- control tower and rangefinder were exchanged for a Type 271 target indication radar mounted above the bridge. By this time, she had been fitted with a high- frequency direction finding system as well. Whilst assigned to Escort Group C1 defending Convoy ON 154 in late December 1942, St. Laurent had her first victory; In the early hours of 27 December 1942, while north of the Azores, she sighted a U-boat on the surface which she engaged with gunfire, followed by a depth charge attack as the boat crash-dived.
Specially constructed Y stations undertook direction finding on wireless transmissions. This became particularly important in the Battle of the Atlantic where locating U-boats was vital. Admiral Dönitz told his commanders that they could not be located if they limited their wireless transmissions to under 30 seconds, but skilled D/F operators were able to locate the origin of their signals in as few as six seconds. The design of land-based D/F stations preferred by the Allies in World War II was the U-Adcock system, which consisted of a small, central operators' hut that was surrounded by four vertical aerial poles, usually placed at the four compass points.
Campbell, along with , were the first U.S. warships equipped with HF/DF, pioneered by the Royal Navy for the fight against the German U-boat fleet. The two cutters had been selected by the Navy to serve as test ships to gain experience with HF/DF, using British FH3 systems (carrying the U.S. designation Type DAR) installed in the American shipyard in Northern Ireland under the supervision of experts from the Admiralty Signals Establishment.P. G. Redgment, "High-Frequency Direction Finding in the Royal Navy: Development of Anti-U-Boat Equipment, 1941-5," in Applications of Radar and Other Electronic Systems in the Royal Navy in World War 2, ed.
Blair conducted shakedown training out of Bermuda before clearing those waters on 2 November in company with . After escorting the oiler to Bermuda, the new destroyer escort sailed to Charleston, South Carolina, where, on 7 November, the ship's SA radar was removed and DAQ HFDF (High Frequency Direction Finding, or "Huff Duff") equipment was installed. Departing Charleston on 14 November, Blair reached New York on 16 November. After shifting to New London, Connecticut, for exercises, she returned to Staten Island, New York, briefly before departing New York in a convoy bound for Hampton Roads, Virginia. From there, the ship helped to screen Convoy UGS-25 to North Africa.
The ship reported its current position as from San Francisco and northeast winds of . However, when Hegenberger tried to obtain a position fix by radio direction finding, the transmitter signal from the Bird of Paradise was too weak for the ship to obtain a bearing. Before dark, and approximately halfway through the flight, the crew attempted to eat their inflight meal, but neither was able to locate the sandwiches or themos bottles. One of them was later quoted as saying the missing food was "the only mishap of the flight", and that they eventually concluded (incorrectly) that the food had never been placed aboard.
The ship's anti aircraft armament was gradually increased, first by fitted a second quadruple machine gun mount, and then by the addition of Oerlikon 20 mm cannons and finally a 2-pounder "pom-pom" anti-aircraft gun, giving an ultimate anti-aircraft outfit of three Oerlikons and one 2-pounder. One 3-pounder saluting gun was re-instated after the war, when Shoreham returned to the Gulf. The ship's anti-submarine armament was also gradually increased during the war, with the number of depth charges carried increasing from 15 to as many as 60–90. Other wartime changes included the fitting of radar and HF/DF radio direction-finding gear.
In contrast to ARA and SCR-274-N receivers, all AN/ARC-5 receivers have automatic volume control and a modified tube complement. The AN/ARC-5 navigation receivers have terminals and a switch to connect a DU-series direction finding loop to the receiver, and have a special audio line for an MX-19/ARC-5 adapter to allow the receiver to serve as an LF/MF localizer for the Navy's short-lived AN/ARN-9 Air-Track (related to ZA, ZAX) instrument landing system. These two capabilities were rarely if ever utilized. Otherwise, equivalent receivers of all three systems can interchange as a unit.
The introduction of portable radio systems in the early 20th century gave rise to the possibility of using radio broadcasters (beacons) as a landmark that would be visible to a radio receiver at very great ranges, hundreds of miles or more. The angle between the navigator and the beacon can be measured by using a simple mechanism known as a loop antenna. As the antenna is rotated around a vertical axis, the strength of the received signal varies, and drops to zero (the null) when the loop is perpendicular to the line to the beacon.Joseph Moell and Thomas Curlee, "Transmitter Hunting: Radio Direction Finding Simplified", TAB Books, 1978, pp. 1–5.
At the start of World War II in September 1939, both the United Kingdom and Germany knew of each other's ongoing efforts in radio navigation and its countermeasures – the "Battle of the beams". Also, both nations were generally aware of, and intensely interested in, the other's developments in radio-based detection and tracking, and engaged in an active campaign of espionage and false leaks about their respective equipment. By the time of the Battle of Britain, both sides were deploying range and direction-finding units (radars) and control stations as part of integrated air defense capability. However, the German Funkmessgerät (radio measuring device) systems could not assist in an offensive role and was thus not supported by Adolf Hitler.
Virginia was the second of three sister ships built by the Newport News Shipbuilding and Drydock Company of Newport News, Virginia for the American Line Steamship Corporation, which at the time was part of J. P. Morgan's International Mercantile Marine Co. She joined () in the fleet of American Lines' Panama Pacific Lines subsidiary. A third sister, SS Pennsylvania, was . Virginia was a steamship, with oil-fired furnaces heating her boilers to power two General Electric steam turbo generators with a combined rating of 2,833 NHP supplying current for her electric propulsion motors. Virginia was equipped with submarine signalling apparatus and wireless direction finding equipment, and from about 1934 she was equipped with a gyrocompass.
XM1201 Reconnaissance and Surveillance Vehicle (RSV) The XM1201 Reconnaissance and Surveillance Vehicle (RSV) featured a suite of advanced sensors to detect, locate, track, classify and automatically identify targets under all climatic conditions, day or night. The suite included a mast-mounted, long-range optoelectronic infrared sensor, an emitter mapping sensor for radio frequency interception and direction finding, chemical sensor and a multifunction radio frequency sensor. The RSV also features the onboard capability to conduct automatic target detection, aided target recognition and level-one sensor fusion. To further enhance the scout's capabilities, the RSV is also equipped with Unattended Ground Sensors, a Small Unmanned Ground Vehicle with various payloads and two unmanned aerial vehicles.
Target-Invisible film Target-Invisible is a 1945 documentary short film produced by the First Motion Picture Unit after World War II. The film depicts the uses of radar in aerial direction-finding and precision high-level bombing by the United States Army Air Forces during World War II. At the end of Target-Invisible, the air force narrator (Arthur Kennedy) thanks Americans for their contributions to the war effort but even though the war is over. The film mentions the dropping of the atom bomb in August 1945. The plea is for Americans to help win the peace by supporting scientific efforts through buying Victory Loan war bonds.Moore and Thompson 1998, p. 71.
In the early 1930s, the Adcock antenna (transmitting in the LF/MF bands) became a key feature of the newly created radio navigation system for aviation. The low frequency radio range (LFR) network, which consisted of hundreds of Adcock antenna arrays, defined the airways used by aircraft for instrument flying. The LFR remained as the main aerial navigation technology until it was replaced by the VOR system in the 1950s and 1960s. The Adcock antenna array has been widely used commercially, and implemented in vertical antenna heights ranging from over 130 feet (40 meters) in the LFR network, to as small as 5 inches (13 cm) in tactical direction finding applications (receiving in the UHF band).
Diagram from Adcock's 1919 patent, depicting a four-element monopole antenna array; active antenna segments are marked in red. diagonal spacing Japanese Adcock direction finder installation for 2MHz in Rabaul Frank Adcock originally used the antenna as a receiving antenna, to find the azimuthal direction a radio signal was coming from in order to find the location of the radio transmitter; a process called radio direction finding. Prior to Adcock's invention, engineers had been using loop antennas to achieve directional sensitivity. They discovered that due to atmospheric disturbances and reflections, the detected signals included significant components of electromagnetic interference and distortions: horizontally polarized radiation contaminating the signal of interest and reducing the accuracy of the measurement.
Frances Elizabeth Somerville Alexander (née Caldwell; 13 December 1908 – 15 October 1958) was a British geologist, academic, and physicist, whose wartime work with radar and radio led to early developments in radio astronomy and whose post-war work on the geology of Singapore is considered a significant foundation to contemporary research. Alexander earned her PhD from Newnham College, Cambridge, and worked in Radio Direction Finding at Singapore Naval Base from 1938 to 1941. In January 1941, unable to return to Singapore from New Zealand, she became Head of Operations Research in New Zealand's Radio Development Lab, Wellington. In 1945, Alexander correctly interpreted that anomalous radar signals picked up on Norfolk Island were caused by the sun.
The Mill Creek Nature Park is located to the south of the former Canadian Forces Station Coverdale which was constructed by the Royal Canadian Navy in 1943 as HMCS Coverdale. The station was designed for radio direction-finding and was operated by the Women's Royal Canadian Naval Service to monitor German communications during WWII. In the late 1950s, the Mill Creek dam was constructed by the Department of National Defence to create an emergency water supply for fire prevention during the Cold War. The station, which was designated HMCS Coverdale, was decommissioned in 1971 and the land became divided into parcels, with a large portion acquired by the Town of Riverview in the early 1980s.
The DRDO's avionics programme has been a success story with its mission computers, radar warning receivers, high accuracy direction finding pods, synthetic aperture radar, Active Phased Array Radar, airborne jammers and flight instrumentation in use across a wide variety of Indian Air Force aircraft and satellites. DRDO labs have developed many electronic warfare systems for IAF and the Indian Army and high- performance Sonar systems for the navy. DRDO also developed other critical military hardware, such as the Arjun Main Battle Tank, and is engaged in the development of the future Infantry Combat Vehicle, the "Abhay". The DRDO is also a member of the trials teams for the T-72 upgrade and its fire control systems.
An experimental section of the Signal School and an Admiralty Signal Establishment had existed since 1917, when the task was devolved from HMS Vernon. It had moved to Eastney to study Radar direction finding, with appointments being made there from 30 December 1935, but the apparatus not arriving until 14 July 1936. With the moving of the main signal school to Leydene House the Admiralty Signal Establishment also moved, in April 1941, and was established in Lythe Hill House, Haslemere. The Production department had been set up in Whitwell Hatch Hotel at Haste Hill, Haslemere by the end of May that year, with a small part of the establishment remaining at the old Signal School in Portsmouth.
Rockefeller, wishing the station's buildings to be compatible with others designed for the park, retained Grosvenor Atterbury, the New York architect who designed the park's gatehouses, to come up with plans for the radio station. Atterbury's plan for the new station included a beautiful residence hall similar to Mr. Rockefeller's residence at Seal Harbor. Artisans from all over the world contributed to the project. This building, and the adjacent power station which was also designed by Atterbury, were listed on the National Register of Historic Places in 2013. On 28 February 1935, the U.S. Navy Radio and Direction Finding Station Winter Harbor was officially commissioned with Chief Radioman Max Gunn in charge of a complement of 11 personnel.
In the 1950s and 1960s, SIGINT personnel flew aboard Navy EA-3B aircraft. As a result of ASA casualties during ground SIGINT in Vietnam, ASA developed its own fleet of tactical SIGINT aircraft, starting with the U-6 Beaver. The reconnaissance mission for these aircraft was indicated with an "R" prefix, hence RU-6. Beavers, however, had poor capabilities. The RU-1 Otter had more built-in SIGINT equipment, but the first purpose-built Army SIGINT aircraft was the RU-8D Seminole, which had a Doppler navigation system and wing-mounted direction-finding equipment, although SIGINT operations still required much manual work. Some RU-8D aircraft had MASINT sensors for categorizing specific transmissions.
The RAF continued to act as a host unit for the resident USAF units, including over time the 6950th United States Air Force Security Squadron, later becoming the 6950th Electronic Security Group and the 7274th Air Base Group. In 1962, a diameter AN/FLR-9 Wullenweber antenna array was constructed at Chicksands to form part of the Iron Horse HF direction finding network. This antenna array, dubbed the Elephant Cage, was dismantled in 1996 when the USAF withdrew from the site, handing it back to the British Armed Forces. During the annual airshow, on 7 July 1979, Colonel Thomas Thompson piloting a Fairchild Republic A-10 Thunderbolt II crashed approximately north of the site and was killed.
Oxford communications aircraft of RAF Marham Station Flight at Blackbushe Airport in September 1955 The Oxford was a low-wing twin- engine cantilever monoplane, featuring a semi-monocoque constructed fuselage, a conventional landing gear configuration and a wooden tail unit. It was capable of reproducing the flight characteristics of many contemporary front- line aircraft then in military service. It was specifically developed to be suitable for a range of training missions, including navigation, flying instruction, night flying, instrument flying, wireless, direction-finding, gunnery, and vertical photography. The Oxford was specifically planned and developed to incorporate various modern innovations and equipment fittings, including a full array of instruments and controls within the cockpit, which assisted in its principal trainer role.
These balloons were tracked by direction finding stations in Ichinomiya, Chiba, in Iwanuma, Miyagi, in Misawa, Aomori, and on Sakhalin to estimate progress toward the United States.Mikesh, pp. 1, 21, 24 The Japanese chose to launch the campaign in November; because the period of maximum jet stream velocity is November through March. This limited the chance of the incendiary bombs causing forest fires, as that time of year produces the maximum North American Pacific coastal precipitation, and forests were generally snow-covered or too damp to catch fire easily. On November 4, 1944, a United States Navy patrol craft discovered one of the first radiosonde balloons floating off San Pedro, Los Angeles.
In 1769, the Spanish Portola expedition became the first Europeans to explore this area by land. Soldiers of the expedition named a nearby point Los Pedernales or Punta Pedernales, because they found flints there. The entire point was given that name on some early maps but, in 1792, British naval explorer George Vancouver dubbed it Point Arguello, for José Darío Argüello, a Spanish frontier soldier who was Commandant of the Presidio of Santa Barbara and acting governor of Alta California. A High-frequency direction finding (HFDF) was established here by the Navy during World War II. These radio intercept sites along the coast could track Japanese warships and merchant marine vessels as far away as the Western Pacific.
New Zealand had a "Combined Intelligence Centre" in Wellington. In 1942 papers from the centre to the C-in-C, Eastern Fleet in Colombo and the RN signals intelligence at Anderson outside Colombo were captured on the Australian steamer Nankin when she was intercepted in the Indian Ocean by the German raider Thor. In the 1930s the New Zealand Division of the Royal Navy established a chain of radio direction finding (D/F) stations from Awarua Radio on the Awarua Plains in Southland, Musick Point near Auckland, Waipapakauri in the far north and Suva, Fiji. There were radio intercept stations at Awarua, Suva, Nairnville in Khandallah near Wellington, and from 1943 at Waiouru.
Mahan stayed in Tampa until 17 February, returning to Norfolk on 21 February. Mahan briefly left at the end of the month to conduct Combat Direction Finding System testing at sea. The next few months saw events including Command Assessment of Readiness and Training (CART), ammunition onload at Yorktown Naval Weapons Station, Tailored Ship’s Training Availability (TSTA), Industrial Hygiene Survey, Combat Systems Ship’s Qualification Trial (CSSQT), evaluation at the Atlantic Undersea Test and Evaluation Center (AUTEC), MISSILEX, Naval Surface Fire Support (NSFS) qualification, VANDALEX, Final Conduct Trial, a post-Shipyard Availability Conference, and a recruiting video shoot, all before the end of July. In August, Mahan hosted the change of command ceremony for Commander Destroyer Squadron 26.
Shortly after taking over command of the ADGB system and combining it into the main Fighter Command network, Hugh Dowding made the installation of high-frequency direction finding, or "huff-duff", sets a priority. In the summer of 1937 he requested that every sector be equipped with three huff-duff sets in order to allow rapid triangulation of the location of fighters. Coincident with this was the deployment of the latest version of the widely used TR.9 radio set, the TR.9B. The Air Staff was slow to respond to Dowding's request due to a shortage of cathode ray tubes (CRTs) used in the huff-duff sets, and by the end of 1937 only five sectors were equipped.
The total cost of the first ship was put at US$1.1 billion, the other US$778 million being for the ship's weapons systems. She was laid down by the Bath Iron Works at Bath, Maine, on 6 December 1988, and launched on 16 September 1989 by Mrs. Arleigh Burke. The Admiral himself was present at her commissioning ceremony on 4 July 1991, held on the waterfront in downtown Norfolk, Virginia. The "Flight II Arleigh Burke" ships have the following improvement over the original Flight I: incorporation of combat direction finding, SLQ-32V-3, TADIX-B, JTIDS command and control processor, and the capability to launch and control SM-2 Block IV Extended Range Missile.
It played a role in the protection of the large concentration of ammunition, ordnance and stores depots established on the Atherton Tableland as part of the assembly and training of Australian troops for the final phase of the New Guinea and island campaigns. Operation of the Radar Station at Bones Knob ceased in December 1944 as the South West Pacific frontline moved further north. Radar in Australia By the late 1930s Britain had become concerned with defence against aerial bombing and the development of radio direction finding systems for air warning and interception was receiving top priority. By contrast Australia's defence strategy was focused on preventing attacks on coastal targets by enemy warships.
On 8 April 1940, No. 11 Operational Training Unit (OTU) was formed at Bassingbourn as part of No. 6 Group from the Station HQ and No 215 Squadron. Equipped with Vickers Wellingtons, its role was to train night bomber crews. From December 1941 to February 1942 the OTU operated from RAF Tempsford while runways were constructed at Bassingbourn. The station was attacked on 5 April 1940 by an isolated German raider that dropped 10 bombs, causing damage to the direction finding equipment and WT (wireless transmitter) huts, and in August 1940 by a single bomb dropped on the barrack block situated immediately south of the parade ground, which killed 11 and injured 15.
German attacks ceased on 13 May after Biter arrived to provide air cover. In October 1943, Whitehall participated in Operation Alacrity, the establishment of air and refuelling bases in the Azores, escorting convoys carrying men, equipment, and supplies to the islands. Later in the month, she returned to convoy escort duty, taking part in the escort of the combined convoys MKS 28 and SL 138. On 31 October, while the convoys were under attack by German submarines of Wolfpack Schill, a radio direction-finding fix on allowed Whitehall and the corvette to depth- charge U-306 and sink her in the North Atlantic northeast of the Azores at with the loss of her entire crew of 51.uboat.
In mid-1931, at the Polish General Staff, a Cipher Bureau was formed by merging the Radio-Intelligence Office (Referat Radiowywiadu) and the Polish-Cryptography Office (Referat Szyfrów Własnych)., note 6 The Bureau was charged with both cryptography — the generation, and supervision of the use, of ciphers and codes — and cryptology, the study of ciphers and codes, particularly for the purpose of "breaking" them. Between 1932 and 1936, the Cipher Bureau took on additional responsibilities, including radio communications between military-intelligence posts in Poland and abroad, as well as radio counterintelligence — mobile direction-finding and intercept stations for the locating and traffic-analysis of spy and fifth-column transmitters operating in Poland.
As soon as the preliminary operation was ready, the Admiralty ordered the operation to be postponed and all light cruisers and the twelve destroyers were to prepare to sail to intercept a German surface force believed to be in the North Sea. The Admiralty code breakers of Room 40 had uncovered the call signs of and and by direction finding, knew that they had sailed from Wilhelmshaven in the Jade Bay to (Lister Deep) north of Sylt. An operation as far north as the Scandinavian collier route was discounted. In the absence of intelligence of German intentions, Admiral David Beatty, the commander of the Grand Fleet, was constrained to scour the North Sea.
France was represented by Gustave Bertrand and Air Force cryptologist Captain Henri Braquenié; Britain, by Government Code and Cypher School chief Alastair Denniston, veteran cryptologist Alfred Dillwyn Knox, and Commander Humphrey Sandwith, head of the section that had developed and controlled the Royal Navy's intercept and direction-finding stations. The Polish hosts included Cipher Bureau chief Gwido Langer, the Bureau's German-Section chief Maksymilian Ciężki, the Bureau's General-Staff-Intelligence supervisor Stefan Mayer, and the three cryptologists Rejewski, Różycki and Zygalski.; ; The Poles' gift of Enigma decryption to their Western allies, five weeks before the outbreak of World War II, came not a moment too soon. Knowledge that the cipher was crackable was a morale boost to Allied cryptologists.
The Toronto Flying Club closed the airport in 1931. During the war the area to the south, between the airstrip and the former Northern Railway of Canada lines, were intensely developed as Research Enterprises Limited, joining a number of other small industrial firms. Between June 1942 and March 1944, the Royal Canadian Air Force (RCAF) operated No. 1 RDF (Radio Direction Finding) School at Leaside, and the station was briefly known as RCAF Station Leaside. Although the airport was replaced with industrial uses, the last hangar (south as the north hangar use to occupied the vacant gap until Eglinton Avenue was extended from Laird east to Don Valley) was not removed until 1971.
F[rederick] A. Kingsley (Basingstoke: Macmillan Press, 1995) As the Royal Navy had already discovered, HF/DF was an important part of combatting the threat posed to Allied convoys by U-boats, and the experience with the interim DAR equipment provided impetus to the U.S. development of its own Type DAQ system.Kathleen Broome Williams "Secret Weapon: U.S. High-Frequency Direction Finding in the Battle of the Atlantic". Annapolis: Naval Institute Press. (October 1, 1996), Sinbad and crew, 1943 When the British and Canadians assumed full responsibility for convoys in the North Atlantic in mid-1943, the U.S. took control of all mid-Atlantic and Mediterranean convoys, where the cutters faced a constant threat from U-boats and the Luftwaffe.
Most Ultra intelligence was derived from reading radio messages that had been encrypted with cipher machines, complemented by material from radio communications using traffic analysis and direction finding. In the early phases of the war, particularly during the eight-month Phoney War, the Germans could transmit most of their messages using land lines and so had no need to use radio. This meant that those at Bletchley Park had some time to build up experience of collecting and starting to decrypt messages on the various radio networks. German Enigma messages were the main source, with those of the Luftwaffe predominating, as they used radio more and their operators were particularly ill-disciplined.
All of the P-14 variants were developed for the long-range detection and tracking of aerial targets and had similar performance characteristics between them. All used a single antenna accomplishing both transmission and reception; the antenna was a large open- frame truncated parabolic antenna, the antenna included a heated de-icing system for extreme conditions. The radars ware capable of modulating their frequency around four pre-set frequencies to counteract active interference and used automatic coherent-compensation for passive interference; both systems able to suppress interference by up to 20 dB. In addition to jammer suppression the P-14 can use five auxiliary antennae for direction finding to locate the jammer.
Although he was unsure of the size of the VC facing D Company, from Smith's reports it appeared to be at least a regular battalion. Intelligence suggested it was likely from the 275th Regiment, although the location of its remaining two battalions were unknown, as was that of D445 Battalion. The whereabouts of the 274th Regiment was equally unclear. While radio direction finding suggested it may have been near Phước Tuy's northern border, three weeks earlier it had been reported close to the western side of the Australian TAOR, and one of its battalions had (incorrectly) been believed involved in an attack on Phú Mỹ in the south-west of the province on 11 August.
The introduction of portable radio systems in the early 20th century gave rise to the possibility of using radio broadcasters (beacons) as a landmark that would be visible to a radio receiver at very great ranges, hundreds of miles or more. The angle between the navigator and the beacon can be taken by using a simple mechanism known as a loop antenna which can be rotated around the vertical axis. As the antenna is rotated, the strength of the received signal varies, and drops to zero (the null) when the loop is perpendicular to the line to the beacon.Joseph Moell and Thomas Curlee, "Transmitter Hunting: Radio Direction Finding Simplified", TAB Books, 1978, pp. 1–5.
Mil Mi-10 at Monino Central Air Force Museum (Moscow) ;izdeliye 60: Product / article number. ;V-10:Prototypes of the Mil Mi-10 helicopter. ;Mi-10:Initial standard long-legged production helicopter ;Mi-10GR: A single production Mi-10 fitted with Grebeshok (Comb) direction finding equipment, for ELINT (Electronic Intelligence) duties, in a pod slung between the undercarriage legs. ;Mi-10K: (K - korotkonogiy - short legged) (NATO - Harke-B) Flying crane helicopter with short-legged narrow-track undercarriage and a ventral gondola for a second pilot. ;Mi-10RVK: (RVK - raketno- vertolyotnyy kompleks - heliborne missile system) Numerous variations of heliborne missile systems were envisaged, but only the 9K74 (aka S-5V) system reached the flight test stage.
50 cal machine gun The avionics of the S-211 were designed to be customisable, allowing the manufacturer to accommodate a customer's various mission requirements. In a typical configuration, the aircraft would be provided a VHF/UHF communications suite, multiple navigation systems, such as an attitude and heading reference system (AHRS), horizontal situation indicator, automatic direction finding (ADF), VHF omnidirectional range and instrument landing system (VOR-ILS), a tactical air navigation system (TACAN) and identification friend or foe (IFF) transponder. Operators can choose to have their S-211s outfitted with modern glass cockpits. The S-211's single JTI5D-4C engine provides a maximum thrust output of 11.12 kN (2,500 lbs) and a specific fuel consumption of 0.57 lb/h/lb.
Military aircraft beacons were manufactured to transmit at 243.0 MHz, in the band commonly used by military aviation. Early in its history, the Cospas-Sarsat system was engineered to detect beacon-alerts transmitted at 406 MHz, 121.5 MHz and 243.0 MHz. Because of a large number of false alerts, and the inability to uniquely identify such beacons because of their old, analogue technology, the Cospas-Sarsat system beginning in 2009 stopped receiving alerts from beacons operating at 121.5 MHz and 243.0 MHz, and now only receives and processes alerts from modern, digital 406-MHz beacons. Many ELTs include both a 406-MHz transmitter for satellite detection and a 121.5 MHz transmitter that can be received by local search crews using direction-finding equipment.
The unit provided direct and general support to the 82d Airborne Division in the form of intelligence collection, analysis, and dissemination; counterintelligence and interrogation; signals intelligence, including ground and air based intercept, jamming, and direction finding; remote battlefield sensors and ground surveillance radar; moving target indicators; and long range surveillance. The unit's lineage included 23 campaign and battle streamers from World War II, the Dominican Republic, Vietnam, Grenada, Panama, and the Persian Gulf. The battalion earned seven Meritorious Unit Commendations, one Army Superior Unit Award, and five foreign unit awards. The 313th Military Intelligence Battalion was also one of the most diverse units in the United States Army, with soldiers holding 47 different military occupational specialties and speaking eight different languages.
Professor Edgar Hayden, then a young engineer in the University of Illinois Radio Direction Finding Research Group, led the reassembly of the Wullenweber, studied the design and performance of HF/DF arrays and researched the physics of HF/DF under contract to the U.S. Navy from 1947 through 1960. Hayden led the design and development of a large Wullenweber array at the university's Bondville Road Field Station, a few miles southwest of Bondville, IL. The array consisted of a ring 120 vertical monopoles covering 2–20 MHz. Tall wood poles supported a circular screen of vertical wires located within the ring of monopoles. His research is still used today to guide the design and site selection of HF/DF arrays.
Eight days later the squadron moved to Hedo Point at the very northern tip of Okinawa where there remained a fair bit of enemy activity. During May 1945 the squadron controlled over 1800 aircraft without the loss of any pilots, assisted in the rescue of eight pilots who bailed out over water, controlled interceptions resulting in the destruction of 45 enemy planes, and with its direction finding station brought eighteen lost planes home. In June, the squadron controlled 503 division of combat air patrol (CAP) aircraft as well as 40 divisions of close air support and strike missions, 94 barrier CAP divisions and 24 air-sea rescue escort divisions. On 19 June, the squadron was joined by a platoon from a United States Army Air Warning Battalion.
The product consisted of an array of eight helical antennas which could be mounted on top of a vehicle, and a control box with a circle of LED direction indicators which was typically mounted inside for viewing by the driver or a passenger. It was originally intended for use in the sport of amateur radio direction finding. Customers included the US Border Patrol, who used it to track dogs they had equipped with radio transmitters, and various taxi companies, who used it to locate drivers who interfered with radio dispatch by continuously transmitting. The product used a digital FIR filter and other advanced digital techniques to continuously determine the direction of the incoming radio signal based on its interaction with the eight separate antennas.
All US submarines, as new construction on the Virginia-class submarines and retrofitted to the Improved Los Angeles-class submarines and possibly Seawolfs, will receive an upgraded Electronic Support (ES) suite, designed as a minimally manned, passive receiving system capable of detection, acquisition, identification, and localization of a variety of signals of interest. ES contains the AN/BLQ-10 SIGINT system, which gives detection, emitter location and MASINT identification, direction finding, and strategic intelligence support. It was first implemented in 2000 and should be in all US submarines by 2012. ES is not limited to the AN/BLQ-10 alone, but a major improvement in receiving, with an expected 200% improvement in performance with the Type 18I periscope and Integrated Electronics Mast (IEM), especially in the littorals.
In preparation for the trip to Howland Island, the U.S. Coast Guard had sent the cutter to the island. The cutter offered many services such as ferrying news reporters to the island, but it also had communication and navigation functions. The plan was the cutter could: communicate with Earhart's aircraft via radio; transmit a radio homing signal to make it easy to find Howland Island without precise celestial navigation; do radio direction finding if Earhart used her 500 kHz transmitter; use an experimental high-frequency direction finder for Earhart's voice transmissions; and use her boilers to "make smoke" (create a dark column of smoke that can be seen over the horizon). All of the navigation methods would fail to guide Earhart to Howland Island.
Large scale radio direction finding (abbr. RDF) was not employed in B-Dienst until the 1930s. The Unit radio reconnaissance operation in 1937–38 had a central control centre in Berlin, three other control centres (North: Neumünster, middle: Soest, South: Langenargen), four main bearing radio sets (Wilhelmshaven, Flensburg, Swinemuende, Pillau) and eight targeting stations along the North and Baltic Coast (Borkum, Cuxhaven, Arkona, Darss, Falshöft, Ustka, Memel, Windau).The network of material collecting bearing points. In: Heinz Bonatz, 1981, S. 368–370 In March 1939, the B-Service observed a total of 36 radio traffic areas, including 14 British, 10 French and 10 Russian. When decoding, the B-Dienst had 20 radio key process desks, of which 7 were English, 5 were French and 4 Russian.
By using direction finding and radio intercept monitoring techniques, from the goniometric stations in Nuremberg, Augsburg and Brest that had formed a triangulation azimuth, the Funkabwehr were able to identify an illegal radio transmission that came from the home of Wenzel at his Brussels home at 12 Rue de Namur. It took some days to identify the correct location due to the layout of the building and the electric railway that ran through the neighbourhood, but on 29–30 June 1942, Captain Harry PiepeHarry Piepe working for section IIIF of the Abwehr in 1942, finally identified the correct apartment. He was interviewed in 1965 by the French journalist Gilles Perrault and an account of this is contained in the Kesaris, Paul. L, ed. (1979).
The MISTE soldiers participated in annual training with the rest of the battalion. Maintaining technical skills was also a problem, as much of the equipment—such as direction-finding trucks, radio intercept trucks, radio jamming trucks, inter alia—was prohibitively expensive for the Army to provide just to have it sit in storage twenty-eight days or more per month. Because of likely damage to streets, the battalion's M113 armored personnel carriers, M577 tactical operations center vehicles and M578 recovery vehicles were stored at Marine Corps Base Camp Pendleton; the three-hour round trip negated monthly training on the tracked vehicles. When Iraq invaded Kuwait in August 1990, the four-year-old battalion was neither adequately manned nor trained for mobilization.
A section headed "America Plans the Mainland SIGINT Buildup, [deleted]-1961" begins with a statement that in 1959, "the problem of American cryptology in Southeast Asia could be seen by looking at a map of SIGINT sites in the larger Asian region." After over a page of deleted material, it was said that most coverage came from three sites in the Philippines, which provided about 450 hours per month of monitoring the DRV. After deletions, the comment is made that the "more general traffic analysis situation was deemed barely sufficient to establish a "skeletal" technical continuity for radio station and network identification and provide data for a realistic estimate of the total communist communications problem. Direction finding support for the DRV transmitters was "insignificant"".
Initially, the Joint Special Operations Command (JSOC), which was in charge of handling terrorist incidents, sent a six-man liaison team of Delta Force and ISA members led by Colonel Jesse Johnson, a senior Delta officer, to offer "technical assistance" to the Italian authorities. Johnson reported to the JSOC headquarters that the Activity should take the job of searching for the kidnapped general. ISA signals intelligence (SIGINT) operators primarily searched for the Red Brigades’ communications networks. As part of this mission, ISA equipped a Bell UH-1 Huey helicopter with the "latest frequency- scanning radio sets and electronic direction-finding equipment." This allowed the SIGINT operators to lock onto and track the Red Brigades’ radio communications even after they changed frequencies.
Leigh-Mallory controlled the air battle from 11 Group headquarters at RAF Uxbridge; commands flowing through the system as normal to Sector control rooms and from there to the airfields.Leigh-Mallory p61 An RAF officer from Hut 3 at Bletchley Park was seconded to the 11 Group Operations Room to filter material to the Y-stations at RAF Cheadle and RAF Kingsdown which intercepted Wireless telegraphy (W/T) and Radio telephony (R/T) transmissions and used direction finding to pinpoint the origin of the signals. The intention was to reduce the time to pass decryptions of material from German radar, observer posts and fighter control to 11 Group through "the most expert officer in Y on German Fighter Defence and its ramifications".
Heightening tensions with Russia and the beginning of The Cold War saw the reactivation of the 603d Tactical Control Squadron under the 7400th Air Force Communications Wing at Hof, West Germany on 25 May 1948. On 1 December 1948 it was redesignated the 603d Aircraft Control and Warning Squadron, under direct control of the 7402d Aircraft Control and Warning Group. Its mission was to provide early warning radar and direction-finding network to support tactical air operations of USAFE and to provide navigational aids to friendly aircraft. The main force of the unit's capabilities were witnessed during the 1948-49 Berlin Airlift. On 10 June 1949 the 603d realigned under the 501st Aircraft Control and Warning Group and on 18 Nov.
Valorous interrupted her regular duties in January 1942 to take part in Operation Performance, deploying with the Home Fleet to cover the break-out of merchant ships from Sweden into the North Sea via the Danish Straits. Fitted with a Type 285 fire-control radar for her main armament in 1942 and with Type 286P radar and direction-finding equipment in 1943–1944, the vessel continued her convoy defense duties through the surrender of Germany in early May 1945, not taking part in any operations related to the Allied invasion of Normandy in the summer of 1944. After Germany's surrender, Valorous supported reoccupation forces, and on 14 May 1945 joined the destroyer in escorting minesweepers during minesweeping operations at Kristiansund, Norway.
The stations with the capability and precise method to use the combined radio, including stations transmitting radio direction finding signals, and submarine signal were published in nautical notices and tables. The Fessenden oscillator, invented by Submarine Signal Company's consulting engineer Reginald Fessenden in 1913 and developed and manufactured in 1914, was a transducer that was easier to install and maintain, could both send and receive, and also allowed coded communication between any two installations, including submarines. Bells were quickly phased out and transducer equipped installations remained active until World War II. The bells had been adequate to send signals, even coded strikes for identification, but the company had been seeking a method of acoustical communications. The oscillator accomplished that and led to further developments in underwater acoustics.
This could be easily arranged by locating another slave station in France or the Netherlands and modifying its delay and signal strength for its signals to appear to be similar to those from one of the stations in the UK. This worked only over Germany; when aircraft flying over the UK the signal would appear too weak. Using conventional radio receivers and loop antennas for direction finding, radio operators could determine which of the signals was false. Even if jammed over enemy territory, Gee had the extremely useful advantage of providing a reliable navigational fix once homeward aircraft were over the North Sea on return from operations, making it easier for returning bombers to find their airfields with a resultant reduction in losses due to accidents.
The Allies failed to respond adequately to several warnings of Japanese activity off the east coast of Australia prior to the attack; they simply ignored the warnings or explained them away. They attributed the unsuccessful attack on the freighter Wellen on 16 May to a single submarine, and assumed it had departed Australian waters immediately after the attack. The first reconnaissance flight went unnoticed, and although FRUMEL intercepted the report and distributed it to Allied commanders on 30 May, Muirhead-Gould apparently did not react. New Zealand naval authorities detected radio chatter between the Japanese submarines on 26 and 29 May, and although they could not decrypt the transmissions, radio direction finding indicated that a submarine or submarines were approaching Sydney.
In 1915, Robert Watson-Watt used radio technology to provide advance warning to airmen and during the 1920s went on to lead the U.K. research establishment to make many advances using radio techniques, including the probing of the ionosphere and the detection of lightning at long distances. Through his lightning experiments, Watson-Watt became an expert on the use of radio direction finding before turning his inquiry to shortwave transmission. Requiring a suitable receiver for such studies, he told the "new boy" Arnold Frederic Wilkins to conduct an extensive review of available shortwave units. Wilkins would select a General Post Office model after noting its manual's description of a "fading" effect (the common term for interference at the time) when aircraft flew overhead.
The stupendous fire delivered by the Allied naval artillery in conjunction with the artillery of the divisions and corps in the beachhead, whose supply of ammunition seemed inexhaustible, as well as the effect of carpet bombing, created a radio psychosis among the German troops. They believed that every tap on the key or a field radio was being pinpointed by small army direction finders and that this was the reason for the allied fire. Consequently, German radio activity was discontinued. It took quite some time to persuade the troops that, in view of the large number of German transmitters employed at the front, enemy direction finding could not possibly be as effective as they feared and that the enemy fire, moreover, was equally heavy at all points.
Opening phase of Operation Barbarossa Chart 9. Armies, Direction finding and Intercept units movements during Signal intelligence operations by Germany in Southern Russian 1941–1942 The vastness of European Russia, its dearth of good roads, the great distances which had to be traversed, the lack of high-capacity long-distance commercial teletype circuits, as well as the shortage of military telephone apparatus and cables, compelled the Soviet Army to make a far greater use of radio communication than was necessary in the armies of the highly industrialized Western countries.German radio intelligence, by Albert Praun, pp. 86–128 During 1941–42, German radio intelligence concentrated mainly on long range operations, which in spite of many difficulties provided the German command with important information about the Red Army.
By concentrating both intercept companies in the Kasatkin-Delaya Tserkov-Uman area in the path of the German 17th and 6th Armies, the strength of the Russian 12th Army in particular was revealed by its radio communications as well as by the direction-finding operations focussed on it. There was an especially high yield of clear-text messages during the Battle of Uman pocket in mid August 1941. The utter confusion on the part of the Russian radio nets, which was reminiscent of the traffic intercepted at the end of the Campaign in the West, spelled an impending collapse. Captured documents not only confirmed the results obtained by radio intelligence evaluations but also provided valuable supplementary information for traffic analysis and message evaluation procedures.
During October 1941 the Sixth and Seventeenth Armies and the 1st Panzer Army reached the Donets and the Mius Rivers and took Kharkov and Rostov. For the purpose of covering the extensive Kharkov area, where the most stubborn resistance was encountered, the 57th Intercept Company was retained at army group headquarters in Poltava and its D/F teams were assigned the area between Lozova and Sumy. The 3rd Intercept Company was moved up to Slavyansk, where it carried out its direction-finding operations on a line from Mariupol on the Sea of Azov to a point west of Izium on the Donets. Coverage of the enemy area as far east as the Don river between Voronezh and Rostov was thus reasonably assured.
During the mid- and late-1930s, radio systems for the detection and location of distant targets had been developed under great secrecy in the United States and Great Britain, as well as in several other nations, notably Germany, the USSR, and Japan. These usually operated at Very High Frequency (VHF) wavelengths in the electromagnetic spectrum and carried several cover names, such as Ranging and Direction Finding (RDF) in Great Britain. In 1941, the U. S. Navy coined the acronym 'RADAR' (RAdio Detection And Ranging) for such systems; this soon led to the name 'radar' and spread to other countries. The potential advantages of operating such systems in the Ultra High Frequency (UHF or microwave) region were well known and vigorously pursued.
Some of these stations also acted as 'Y' stations to collect German messages, but a new section was created within Room 40 to plot the positions of ships from the directional reports. A separate set of five stations was created in Ireland under the command of the Vice Admiral at Queenstown for plotting ships in the seas to the west of Britain and further stations both within Britain and overseas were operated by the Admiral commanding reserves. The German navy knew of British direction-finding radio and in part this acted as a cover, when information about German ship positions was released for operational use. The two sources of information, from directional fixes and from German reports of their positions, complemented each other.
Ramsayville is a rural community on Ramsay Creek in Gloucester-Southgate Ward in Ottawa, Ontario, Canada. Prior to 2001, the community was located within the City of Gloucester. The immediate area around Ramsayville (North by the eastern prolongation of Hunt Club Road and Highway 417, west by Hawthorne Road, south by Leitrim Road and east by Anderson Road) has a population of about 90 (2011 Census)Population calculated by combining Census Blocks 3506148214, 3506148215, 3506148226 and 3506148233 The community was also a site used for High Frequency Direction Finding experiments by the Royal Canadian Navy. The Navy installation was located on Ramsayville Road (then known as Base Line Road) about five miles from Gloucester near the intersection of Leitrim Road.
The German fleet was in the habit each day of wirelessing the exact position of each ship and giving regular position reports when at sea. It was possible to build up a precise picture of the normal operation of the High Seas Fleet, indeed to infer from the routes they chose where defensive minefields had been placed and where it was safe for ships to operate. Whenever a change to the normal pattern was seen, it immediately signalled that some operation was about to take place and a warning could be given. Detailed information about submarine movements was also available. Both the British and German interception services began to experiment with direction finding radio equipment at the start of 1915.
The restored Operations Room in the underground bunker at RAF Uxbridge showing the map and plotters and with the RAF Station names and readiness status boards on the wall behind. Also shown is the Sector clock In the original Dowding system of fighter control, information from the Chain Home coastal radar stations was relayed by phone to a number of operators on the ground floor of the "filter room" at Fighter Command's headquarters at RAF Bentley Priory. Here the information from the radar was combined with reports from the Royal Observer Corps and radio direction finding systems and merged to produce a single set of "tracks", identified by number. These tracks were then telephoned to the Group headquarters that would be responsible for dealing with that target.
In early 1939, Henderson was selected to represent Canada in a series of highly classified briefings in Great Britain concerning developments in the Air Ministry on Range and Direction Finding (RDF – later called radar). This was largely coordinated by Robert Watson-Watt at RAF Bawdsey, with the purpose of preparing the Commonwealth of Nations to have indigenous developments in this technology. Upon Henderson's return from the briefings in England, arrangements were made between the Canadian and American governments for him to visit a number of facilities in the U.S. Following this, he prepared a detailed report that included proposed plans for bringing the NRC into the RDF activities. Within a short time, he was authorized to set up a development laboratory for this in the NRC Radio Section.
Digital avalanche transceiver with LED display An avalanche transceiver or avalanche beacon is a type of emergency locator beacon, a radio transceiver (a transmitter and receiver in one unit) operating at 457 kHz for the purpose of finding people buried under snow. They are widely carried by skiers, particularly cross-country skiers for use in case a skier is buried by an avalanche. When the owner sets out on a skiing descent, the transmitter is activated, causing the device to emit a low-power pulsed radio signal during the trip. Following an avalanche, if some members of the ski party are buried, the others may switch their transceivers from transmit into receive mode, allowing use as a radio direction finding device to search for signals coming from the lost skiers.
This made RDF much more practical, especially on large vehicles like ships or when using very long wavelengths that demand large antennae. BTDF was invented by a pair of Italian officers in the early 1900s, and is sometimes known as a Marconi–Bellini–Tosi after they joined forces with the Marconi Company in 1912. BTDF was the most prevalent form of naval direction finding from the 1920s to well into the 1980s, and was used as a major part of early long- distance air navigation systems from the 1930s until after World War II. BTDF systems were also widely used for military signals intelligence gathering. During the war, new techniques like huff-duff began to replace radiogoniometers in the intelligence gathering role, reducing the time needed to take an accurate fix from minutes to seconds.
Important requirements are that no transmitter may be within 750 meters of the start, no transmitter may be within 400 meters of the finish or any other transmitter on course, and that there is no more than 200 meters elevation change between the start, finish, and all transmitters. The IARU rules for international competitions recommend that courses be designed for six to ten kilometers of total travel distance through the terrain. A well-designed course will present the competitors with an athletic challenge in addition to the challenges of land navigation and radio direction finding. Depending on the course design and competition, winning times at World Championship events are often less than 90 minutes for two meter courses, and can be under 60 minutes for eighty meter courses.
On his arrival in England, Struszynski joined the staff of HM Signal School (later called the Admiralty Signal Establishment), and in a very short time, he not only proposed a solution to the problem of signal reflection, but also introduced 'sense' into the antenna, to distinguish between radio signals arriving from the correct direction to those offset by 180 degrees. He also led a team at HM Signal School that developed a practical antenna, which enabled effective high frequency direction finding systems to be installed on Royal Navy convoy escort ships. A comprehensive account of the work on HF/DF at HM Signal School is given by Redgment, who worked with Struszynski during and after the war, and details of the antenna are described by Struszynski et al., and by Bauer.
In 1953, St Johnston left the British Non- Ferrous Metals Research Association and joined Borehamwood Laboratories of Elliott Brothers (London) Ltd, where she worked in the Theory Division. The company was an early computer company and had produced its first computer in 1950. St Johnston learned to programme at the company and also at the 1954 Cambridge Summer School on Programming and, showing a real flair for programming, began working on EDSAC and the Elliott 400 and 800 series computers. By 1954, St Johnston was responsible for the programming of the Elliott 153 Direction Finding (DF) digital computer for the Admiralty and soon after for programming Elliott’s own payroll computer; her work was said to have been inventive and structured, but also very accurate, hardly ever requiring ‘de-bugging’.
In 1936, Nissenthall was talent scouted by the R.A.F and given an apprenticeship which involved him working during his free time at the experimental radar station at Bawdsey Manor in Suffolk, thus involving him at a critical period in the pioneering work of Robert Watson-Watt and his team. On the outbreak of war in September 1939, Nissenthall volunteered for service in the R.A.F. His request for flight duties was refused and instead he was posted to R.A.F Yatesbury where he was assigned to the first R.D.F (Radio Direction Finding) training school in Britain. Thereafter he was posted to various radar installations across the country. His skills and his abilities were increasingly being recognised by higher authority, as indicated by his suggestions for technical improvement of equipment being regularly accepted without question.
This explanation allowed the investigation team to decide it was British Huff-Duff that explained this case. The team also found two additional scenarios which could reinforce British direction-finding as the cause and tie it to the information in the Situation Report, and that involved the U-boats themselves: :...it is very possible that the U-boats...either had developed traffic among themselves or had attempted, at an inopportune time, to signal the base, without this attempt being noticed, whereas the English D/F service had succeeded nonetheless in an approximate tactical location [of the submarine]. With this, the Kriegsmarine settled for an explanation of the excellent British D/F, radar and other locating services. This belief in the superior quality of British location systems would emerge throughout these investigations into Enigma security.
The difference of the group time delay of a lighting pulse at adjacent frequencies is proportional to the distance between transmitter and receiver. Together with the direction finding method, this allows locating lightning strikes by a single station up to distances of 10000 km from their origin. Moreover, the eigenfrequencies of the Earth- ionospheric waveguide, the Schumann resonances at about 7.5 Hz, are used to determine the global thunderstorm activity.Volland, H. (ed): "Handbook of Atmospheric Electrodynamics", CRC Press, Boca Raton, 1995 Because of the difficulty in obtaining distance to lightning with a single sensor, the only current reliable method for positioning lightning is through interconnected networks of spaced sensors covering an area of the Earth's surface using time- of-arrival differences between the sensors and/or crossed-bearings from different sensors.
LAFFING EAGLE increased RU-21 series capability by adding a second SIGINT operator, receivers with a greater frequency range, and an AN/ASN-86 Internal Navigation System. The new system proved very difficult to maintain, however, requiring constant support from contractor representatives and a trailer full of test equipment. Later on, the V-SCAN system, which gave 240-degree direction- finding coverage centered around the nose and tail, was added to the RU-21Ds. Those aircraft arrived in Vietnam in December 1968 and heavily used. WINE BOTTLE and CEFISH PERSON systems, on RU-6A and RU-8D aircraft, were generally unsatisfactory and the 156th Radio Research Company, using these aircraft, redeployed to the US. These aircraft were incapable of true goniometric ARDF, and had to fly over the emitter, dangerously, before pinpointing it.
A separate SIGINT and communications security organization, or Service Cryptologic Element (SCE), existed for the US Army, Navy, and Air Force. Some of the differences were quite appropriate to support of the military operations of the particular service; the Air Force would be interested ELINT about air defense radars that a bomber might take in attacking the Soviet Union over a polar route, while the Navy would be more interested in coastal air defense radars. The Army would want to be able to recognize hostile artillery fire control radars, and also how to do tactical direction finding, traffic analysis, and field-level cryptanalysis against opposing ground forces. All of these services also had capabilities to provide national-level intelligence more appropriate for NSA's mission than for support to military operation.
The original 16th-century parts of fortifications such as Southsea and Calshot were too small and unsuitable for modern weapons, however, and were instead used for mounting searchlights, range and direction finding; in some cases their fabric was left to slowly decline.; ; ; Some other sites were no longer considered viable at all. West Cowes was decommissioned in 1854 and became the club house of the Royal Yacht Squadron. Sandown Castle in Kent, suffering badly from coastal erosion, began to be demolished from 1863 onwards; Hull Citadel and its 16th-century fortifications were demolished in 1864 to make way for docks; Yarmouth was decommissioned in 1885, becoming a coastguard signalling station; and Sandgate, also suffering from coastal erosion, was sold off to the South Eastern Railway company in 1888.
Flynn similarly contended that the German bombing of Dundalk on 4 July was also a pre-warning by Lord Haw Haw as a punishment for Dundalk being the point of shipment of Irish cattle sold to the United Kingdom. After the war Winston Churchill said that "the bombing of Dublin on the night of 30 May 1941, may well have been an unforeseen and unintended result of our interference with 'Y'." He was speaking of the Battle of the Beams, wherein "Y" referred to the direction finding radio signals that the Luftwaffe used to guide their bombers to their targets. However, the technology was not sufficiently developed by mid-1941 to have deflected planes from one target to another, and could only limit the ability of bombers to receive the signals.
During the first few years of World War II, the Ubootwaffe ("U-boat force") scored unprecedented success with these tactics ("First Happy Time"), but were too few to have any decisive success. By the spring of 1943, German U-boat construction was at full capacity, but this was more than nullified by increased numbers of convoy escorts and aircraft, as well as technical advances like radar and sonar. High Frequency Direction Finding (HF/DF, known as Huff-Duff) and Ultra allowed the Allies to route convoys around wolfpacks when they detected radio transmissions from trailing boats. The results were devastating: from March to July of that year, over 130 U-boats were lost, 41 in May alone. Concurrent Allied losses dropped dramatically, from 750,000 tons in March to 188,000 in July.
There was a saying in the 1970s that if the intelligence units were able to effectively do their job, the combat units wouldn't have to do theirs. The Station's mission was to monitor the communications of Cold War enemy nations, their allies, and client states around the world. The information gathered was time-sensitive and, based on its importance and classification, that information was collected, analyzed and passed through intelligence channels on a "real-time" basis. Personnel assigned to the 1st, 2nd, and 3rd Operations Battalions, and the successor Military Intelligence (MI) units (701st Military Intelligence Brigade - 711th, 712th, 713th, & 714th MI Battalions respectively) at Field Station Augsburg served as Morse and non-Morse Cryptologists, Voice Intercept, and Radio Direction-Finding Operators, as well as Traffic Analysts and Cryptanalysis/Cryptanalytic Technicians.
Throughout the war the Royal Canadian Navy (RCN) maintained a communications station at RCAF Station Gander, Its main task was High Frequency Direction Finding (HFDF) and communications monitoring of German U-boat radio transmissions. The United States Army Air Forces Antisubmarine Command assigned several squadrons of long-range antisubmarine aircraft (B-24 Liberator, B-18 Bolo) to fly killer-hunter flights over the Grand Banks and also provide convoy escort overflights from Newfoundland. After the fall of 1943, these missions were undertaken by the United States Navy. The RCAF handed operation of the airfield back to the Government of Newfoundland in March 1946 and removed its presence at what was promptly renamed Gander Airport (it was later upgraded to international status), although the RCN's radio monitoring station remained in operation.
Lusitania entering the left As the liner steamed across the ocean, the British Admiralty had been tracking the movements of , commanded by Kapitänleutnant Walther Schwieger, through wireless intercepts and radio direction finding. The submarine left Borkum on 30 April, heading north-west across the North Sea. On 2 May, she had reached Peterhead and proceeded around the north of Scotland and Ireland, and then along the western and southern coasts of Ireland, to enter the Irish Sea from the south. Although the submarine's departure, destination, and expected arrival time were known to Room 40 in the Admiralty, the activities of the decoding department were considered so secret that they were unknown even to the normal intelligence division which tracked enemy ships or to the trade division responsible for warning merchant vessels.
He knew that the essential element for any day/night air defense capability was a robust system of ground based radar. One of his first official tasks was to brief then Commandant of the Marine Corps (CMC) LtGen Thomas Holcomb on what he had seen in England and what he recommended going forward. When he informed CMC that the current purchase of 12 x SCR-268 radars for the defense battalions was not sufficient and that they would need a mix of 50+ radars at a minimum, the Commandant replied, “Gee whiz, that an awful lot.” He left that meeting having not been told no, so newly promoted Major Dyer immediately piggy backed onto an existing US Army purchase and placed an order, sight unseen, for 23 million dollars’ worth of VHF radios, VHF direction finding equipment, IFF equipment and GCI radars.
Emergency position-indicating radio beacons (EPIRBs)Emergency Position-Indicating Radio Beacons (EPIRBs) are a development of the ELT designed specifically for use on boats and ships, and basic models tend to be less expensive than ELTs (average cost is $800). As such, instead of using an impact sensor to activate the beacon, they typically use a water-sensing device or a submerged-sensing device that activates and releases a floating beacon after it has been submerged in between 1 and 4 meters of water. In addition to the 406 MHz signal mandated by C/S T.001, the IMO and ICAO require an auxiliary 121.5 MHz at another frequency in order to support the large installed base of 121.5 MHz direction finding equipment. The RTCM (Radio Technical Commission for Maritime Services) maintains specifications specific to EPIRB devices.
USS Kearsarge with the escorts of her hunter-killer group at San Diego in 1961 Hunter-killer Groups, also known as Convoy Support Groups, were groups of anti-submarine warships that were actively deployed to attack submarines during World War II. The advances in signals intelligence such as High- frequency direction finding, in cryptological intelligence such as Ultra, and in detection technologies such as radar and sonar/ASDIC enabled the Allied navies to form flotillas designed actively to hunt down submarines and sink them. Similar groups also existed during the Cold War. A hunter-killer group would typically be formed around an escort carrier to provide aerial reconnaissance and air cover, with a number of corvettes, destroyers, destroyer escorts, frigates, and/or United States Coast Guard Cutters armed with depth charges and Hedgehog anti-submarine mortars.
Eventually, their missions focused on Southeast Asia. ;First-generation Army tactical SIGINT aircraft RU-6A Beaver aircraft equipped with airborne radio direction finders (ARDF) were the first Army reconnaissance aircraft in South Vietnam, arriving in March 1962 and assigned to the Flight Detachment of the 3rd Radio Research Unit. More RU-6A's, now code named SEVEN ROSES, arrived in 1963, along with RU-5D Seminoles with the code name CHECKMATE, and a RU-8F. Initial direction finding was unsatisfactory, and various additional aircraft were added, including more RU-6A and RU-8Ds, a single RCV-2B Caribou codenamed PATHFINDER, a RU-1A Otter coded CAFE GIRL, and RU-1As under the codes HAPPY NIGHTS and LAFFING OTTER. CHECKMATE, with AN/ARD-15 surveillance equipment, proved successful, and was extended to the Beavers and the U-8Ds.
Naval gunboats launched a mock attack on the castle, which responded by firing a volley of forty 8-inch guns, causing chaos among the crowds watching around the base of the fortification.; Fresh worries about France, combined with the development of rifled cannon and iron- clad warships, led to the Royal Commission on the Defence of the United Kingdom expressing fears about the security of Portsmouth in 1860. Lieutenant- Colonel Jervois oversaw the broader programme of work across the country, and was supported at Southsea by Lieutenant-Colonel Fisher. New gun batteries with underground magazines were constructed on the west and east sides of the castle between 1863 and 1869 to form part of a complex enclosed by a defensive wall; the old castle was used for range and direction finding, rather than to house weapons, and was left to slowly decline.
Pip-squeak was a radio navigation system used by the British Royal Air Force during the early part of World War II. Pip-squeak used an aircraft's voice radio set to periodically send out a 1 kHz tone which was picked up by ground- based high-frequency direction finding (HFDF, "huff-duff") receivers. Using three HFDF measurements, observers could determine the location of friendly aircraft using triangulation. Pip-squeak was used by fighter aircraft during the Battle of Britain as part of the Dowding system, where it provided the primary means of locating friendly forces, and indirectly providing identification friend or foe (IFF). At the time, radar systems were sited on the shore and did not provide coverage over the inland areas, so IFF systems that produced unique radar images were not always useful for directing interceptions.
At least into the 1970s, the U.S. National Security Agency (NSA) produced a variety of manual one-time pads, both general purpose and specialized, with 86,000 one-time pads produced in fiscal year 1972. Special purpose pads were produced for what NSA called "pro forma" systems, where “the basic framework, form or format of every message text is identical or nearly so; the same kind of information, message after message, is to be presented in the same order, and only specific values, like numbers, change with each message.” Examples included nuclear launch messages and radio direction finding reports (COMUS). General purpose pads were produced in several formats, a simple list of random letters (DIANA) or just numbers (CALYPSO), tiny pads for covert agents (MICKEY MOUSE), and pads designed for more rapid encoding of short messages, at the cost of lower density.
A typical oscilloscope with a time base controlled on the top dial, and the amplification of the signal on the bottom dial. A cathode ray tube (CRT) consists of three primary parts, the electron gun that provides a stream of accelerated electrons, the phosphor-covered screen that lights up when the electrons hit it, and the deflection plates that use magnetic or electric fields to deflect the electrons in-flight and allows them to be directed around the screen. It is the ability for the electron stream to be rapidly moved using the deflection plates that allows the CRT to be used to display very rapid signals, like those of a television signal or to be used for radio direction finding (see huff-duff). Many signals of interest vary over time at a very rapid rate, but have an underlying periodic nature.
A typical oscilloscope with a time base controlled on the top dial, and the amplification of the signal on the bottom dial. A cathode ray tube (CRT) consists of three primary parts, the electron gun that provides a stream of accelerated electrons, the phosphor-covered screen that lights up when the electrons hit it, and the deflection plates that use magnetic or electric fields to deflect the electrons in-flight and allows them to be directed around the screen. It is the ability for the electron stream to be rapidly moved using the deflection plates that allows the CRT to be used to display very rapid signals, like those of a television signal or to be used for radio direction finding (see huff-duff). Many signals of interest vary over time at a very rapid rate, but have an underlying periodic nature.
Amongst squadrons formed at Andover was 106 Squadron, formed on 30 September 1917, who were equipped with Royal Aircraft Factory R.E.8 reconnaissance aircraft for army co-operation duties, being posted to Ireland in May 1918. Also, from 24 December 1917 to 6 June 1918 Andover was host to a detachment of the 13th Aero Squadron of the Aviation Section, U.S. Signal Corps. In early 1918 experiments were conducted with Handley Page Type O bombers, based at Andover and Cranwell, fitted with Radio Direction-Finding (RDF as it was called) equipment for night flying. The intention was to guide British bombers to and from Berlin, and early results led to 550 sets of RDF equipment being ordered by the United States Army Air Service, but the First World War ended before any attempts could be made to use the system operationally.
Russian radio traffic during the final stage or the fighting in the Crimea was far less disciplined. After the Germans had occupied the peninsula with the exception of Sevastopol, which was no longer of interest from a long-range intelligence point of view, the 7th Intercept Company was moved north in early June 1942 in order to increase the coverage or the Kharkov area. Abandoning its long and medium wave direction-finding operations for the time being, the company was employed for intercept purposes only, after experiments had shown that reception of short-wave signals from the Kuban and Caucasus areas was more favourable, or at least of equal quality, at a greater distance from the objective. The 3rd Intercept Company stationed at Donetsk was given the task of covering the area east or the lower Don.
After 28 May, approximately the time of the Belgian capitulation, it was no longer possible to distinguish the various radio nets and to observe and evaluate them systematically. Continued direction-finding operations indicated that the encirclement area has been split up into three pockets: a northern one, east of Dunkirk, from which mostly British traffic was heard; a central pocket, northwest of Roubaix; and a southern pocket, southeast of Lille. Because of the concentration of a great number of transmitters within one narrow area, it was no longer possible to take accurate bearings. The intermingling of different units was reflected by the confusion which was beginning to spread among the radio operators, who no longer felt bound by any rules, all of which resulted in a situation which in German radio terminology is described as a call sign and wave-length stew.
Zimmermann telegram as decoded by Room 40 All British ships were under instructions to use radio as sparingly as possible and to use the lowest practical transmission power. Room 40 had benefited greatly from the free chatter between German ships, which gave them many routine messages to compare and analyse, and from the German habit of transmitting at full power, making the messages easier to receive. Messages to Scapa were never to be sent by wireless, and when the fleet was at sea, messages might be sent using lower power and relay ships (including private vessels), to make German interception more difficult. No attempts were made by the German fleet to restrict its use of wireless until 1917 and then only in response to perceived British use of direction finding, not because it believed messages were being decoded.
Survivors from after being sunk by , 17 April 1943 Advances in convoy tactics, high-frequency direction finding (referred to as "Huff-Duff"), radar, active sonar (called ASDIC in Britain), depth charges, ASW spigot mortars (also known as "hedgehog"), the intermittent cracking of the German Naval Enigma code, the introduction of the Leigh light, the range of escort aircraft (especially with the use of escort carriers), the use of mystery ships, and the full entry of the U.S. into the war with its enormous shipbuilding capacity, all turned the tide against the U-boats. In the end, the U-boat fleet suffered extremely heavy casualties, losing 793 U-boats and about 28,000 submariners (a 75% casualty rate, the highest of all German forces during the war). At the same time, the Allies targeted the U-boat shipyards and their bases with strategic bombing.
No attempts were made by the German fleet to restrict its use of wireless until 1917, and then only in response to perceived British use of direction finding, not because it believed messages were being decoded. Room 40 played an important role in several naval engagements during the war, notably in detecting major German sorties into the North Sea that led to the battles of Dogger Bank and Jutland when the British fleet was sent out to intercept them. However its most important contribution was probably in decrypting the Zimmermann Telegram, a telegram from the German Foreign Office sent via Washington to its ambassador Heinrich von Eckardt in Mexico. In the Telegram's plain text, Nigel de Grey and William Montgomery learned of the German Foreign Minister Arthur Zimmermann's offer to Mexico to join the war as a German ally.
An intermediate frequency was first used in the superheterodyne radio receiver, invented by American scientist Major Edwin Armstrong in 1918, during World War I. A member of the Signal Corps, Armstrong was building radio direction finding equipment to track German military signals at the then-very high frequencies of 500 to 3500 kHz. The triode vacuum tube amplifiers of the day would not amplify stably above 500 kHz, however, it was easy to get them to oscillate above that frequency. Armstrong's solution was to set up an oscillator tube that would create a frequency near the incoming signal, and mix it with the incoming signal in a 'mixer' tube, creating a 'heterodyne' or signal at the lower difference frequency, where it could be amplified easily. For example, to pick up a signal at 1500 kHz the local oscillator would be tuned to 1450 kHz.
Anaren was founded by Hugh A. Hair and Carl W. Gerst in 1967. Both were RF engineers who left General Electric to focus on a new company that would develop several new RF technologies, including the circuit-etching technologies called stripline manufacturing. The company started with a few dozen employees and a small facility in Syracuse, New York and its first customers were many manufacturing firms in the U.S. defense and aerospace sector including Hughes, Litton Industries (now part of Northrup Grumman), and Raytheon. Contracts and assignments secured during the company's early years included: a microwave landing system for jetliners funded by the United States Department of Defense under FAA supervision; "wideband microwave tracking receivers" for use in direction-finding systems; and the company’s first DFD (digital frequency discriminators) and ESM (electronic support measures) to help fighter jets and seaborne vessels detect, identify, and elude the radar signals of hostile craft.
The then state-of-the-art metre- wavelength Airborne Interception radar, known in British parlance of the time as RDF (Radio Direction Finding) equipment, was bulky and, due to the operator workload, generally unsuited to carriage by single-engined fighters, and so required a twin-engine design. However, the early radar-equipped Bristol Blenheims lacked the necessary speed advantage over the German Heinkel 111s and Dornier Do 17 bombers then raiding the UK to be truly effective, the Blenheim being able to find the bomber, but often not being fast enough to be able to reach a position in which to shoot it down. Non-RDF equipped single- engined fighters, whilst being fast enough to catch the bombers, simply could not find the bombers to shoot them down. In addition, there was some doubt as to the best way to find, intercept and shoot down attacking bombers at night.
In the Air Ministry he read up everything he could find on the art of air defence, and became alarmed. Working at that time for Harry Wimperis, he wrote a memo to him that concluded that "we were likely to lose the war if it starts within the next ten years". Wimperis took the report seriously, and in 1934 started the formation of what later became known as the Tizard Committee, which supported the early development of radio-based detection. In 1935, Rowe coined the acronym RDF as a cover for the work, meaning Range and Direction Finding but suggesting the already well-known Radio Directing Finding technology. Rowe replaced Robert Watson-Watt as Superintendent of the Bawdsey Research Station where the Chain Home RDF system was developed, and in 1938–1945 was the Chief Superintendent of the Telecommunications Research Establishment (TRE), which carried out pioneering research on microwave radar.
For example, if a certain emitter is known as the radio transmitter of a certain unit, and by using direction finding (DF) tools, the position of the emitter is locatable; hence the changes of locations can be monitored. That way we're able to understand that this certain unit is moving from one point to another, without listening to any orders or reports. If we know that this unit reports back to a command on a certain pattern, and we know that another unit reports on the same pattern to the same command, then the two units are probably related, and that conclusion is based on the metadata of the two units' transmissions, and not on the content of their transmissions. Using all, or as much of the metadata available is commonly used to build up an Electronic Order of Battle (EOB) – mapping different entities in the battlefield and their connections.
Chamberlain, Daladier, Hitler, Mussolini, and Ciano pictured before signing the Munich Agreement, which gave the Sudetenland to Germany. Initially the Prime Minister, Neville Chamberlain, was not keen on the idea and still hoped to avoid war, but following his appeasement of Hitler at Munich in September 1938, which was widely seen as a stopgap measure to buy time, he too began to realise the need for urgent preparations for war. During the last 12 months of peace, Britain and France carried out a vigorous buildup of their armed forces and weapons production. The long-awaited Spitfire fighter began to enter service, the first of the new naval vessels ordered under the 1936 emergency programme began to join the fleet, and the Air Ministry made the final touches to the Chain Home early warning network of radio direction-finding (later called radar) stations, to bring it up to full operational readiness.
The twelve codes communicated several different orders which included: informing the crew they were being plotted; change of bearing; degree of bearings (made in multiples of five); port or starboard turns; height; straight and level course; open bombs doors; pre-release signal; bomb or flare release; acknowledgement of signal; return home. The crew responded by switching the set off for three to four seconds to acknowledge receipt of the signal or repeatedly switched off the FuG 25 to indicate they had not received it. When the British radio counter-measures began to interfere with messages the Luftwaffe broadcast in both W/T and R/T format over two channels. The FuG 16 would handle incoming transmissions from the R/T frequencies and the W/T messages were received by the Peilgerät (PeilG) 6 (codenamed "Alex Sniatkowski") direction finding equipment and superimposed on the plotting table.
The "Y" stations tended to be of two types, for intercepting of the signals and for identifying where they were coming from. Sometimes both functions were operated at the same site, with the direction finding (D/F) hut being a few hundred metres from the main interception building, because of the need to minimise interference. The sites collected radio traffic which was then either analysed locally or if encrypted, passed for processing initially to Admiralty Room 40 in London and during World War II to the Government Code and Cypher School at Bletchley Park in Buckinghamshire. Arkley View 1943 In the Second World War a large house called "Arkley View" on the outskirts of Barnet (now part of the London Borough of Barnet) acted as a data collection centre, where traffic was collated and passed to Bletchley Park and it also acted as a Y station.
The four returned to America after ten weeks, with a naval radio direction finding unit and many documents, including a "paper Enigma". The main American response to the 4-rotor Enigma was the US Navy bombe, which was manufactured in much less constrained facilities than were available in wartime Britain. Colonel John Tiltman, who later became Deputy Director at Bletchley Park, visited the US Navy cryptanalysis office (OP-20-G) in April 1942 and recognised America's vital interest in deciphering U-boat traffic. The urgent need, doubts about the British engineering workload and slow progress prompted the US to start investigating designs for a Navy bombe, based on the full blueprints and wiring diagrams received by US Navy Lieutenants Robert Ely and Joseph Eachus at Bletchley Park in July 1942. Funding for a full, $2 million, Navy development effort was requested on 3 September 1942 and approved the following day.
BuPers convened a conference on the ETP in December 1943, at which time the secondary school was increased from 5 months to 24 weeks with new topics added (especially sonar). (This same conference defined Pre-Radio to be 4 weeks and Primary to be 12 weeks.) The ARM secondary school began with a brief review of electronic components, circuits, and basic laboratory instruments. As the courses evolved, they eventually included the following topics: high-frequency and ultra-high-frequency receiver and transmitter principles; coaxial cable, waveguides, antenna arrays, and beam forming; synchros and plan position indicators; radio direction-finding; pulse-generation and wave-shaping methods; basic radar theory; microwave theory and cavity magnetrons; radar jamming and countermeasures; identification friend or foe techniques; long- range navigation and hyperbolic navigation techniques; and sonar theory and underwater acoustics. Laboratories included the use of all types of electronic test equipment.
The Royal Australian Air Force constructed 25 RDF stations in northern Queensland, covering the area from Mackay to the Torres Strait, the Atherton Tableland, Cloncurry district and the Gulf of Carpentaria. No.53 RDF Station at Mount Surprise was a key link in the detection of low flying aircraft heading from the Japanese- occupied Dutch East Indies via the Gulf of Carpentaria in the direction of Townsville or the Atherton Tableland, in the Cairns hinterland, where many Australian and American military units were undergoing jungle warfare training. Its other roles were to provide assistance to the Catalina flying boats returning to base in Townsville, following long-range patrol over Java and in the training of radar personnel prior to postings to "active" areas. Radio Direction Finding technology - later termed Radar to follow the American terminology - was developed by the British during the lead up to the second world war and was quickly shared with its major allies, including Australia.
In its simplest implementation, APRS is used to transmit real-time data, information and reports of the exact location of a person or object via a data signal sent over amateur radio frequencies. In addition to real-time position reporting capabilities using attached GPS receivers, APRS is also capable of transmitting a wide variety of data, including weather reports, short text messages, radio direction finding bearings, telemetry data, short e-mail messages (send only) and storm forecasts. Once transmitted, these reports can be combined with a computer and mapping software to show the transmitted data superimposed with great precision upon a map display. While the map plotting is the most visible feature of APRS, the text messaging capabilities and local information distribution capabilities, combined with the robust network, should not be overlooked; the New Jersey Office of Emergency Management has an extensive network of APRS stations to allow text messaging between all of the county Emergency Operating Centers in the event of the failure of conventional communications.
The Luftwaffes technical edge was slipping away. A front line experience report of the Luftwaffenbefehlshaber Mitte covering the last quarter of 1941, contained a myriad of complaints, including inadequate early-warning and direction- finding radar, lack of Zerstörer (Destroyer) aircraft with all weather capabilities and the poor climbing power of the Bf 109. Generalfeldmarschall Erhard Milch was to assist Ernst Udet with aircraft production increases and introduction of more modern types of fighters. However, they explained at a meeting of the Reich Industrial Council on 18 September 1941 that the new next generation aircraft had failed to materialise, and that obsolescent types such as the Heinkel He 111 bomber and Junkers Ju 87 Stuka dive bomber had to be continued to keep up with the growing need for replacements. > We are simply faced with the question of whether we are to have no aircraft > at all in 1943 or are to have large numbers of aircraft types which hitherto > have proved adequate.
Although the Paris Peace Accords had officially ended the United States' direct role in the Vietnam War, only a week after its signing the U.S. Air Force sent an EC-47Q electronic warfare collection aircraft on a night-time radio-direction-finding mission to monitor the Ho Chi Minh trail and locate North Vietnamese tanks moving south. The plane, tail number 43-48636, belonged to the 361st Tactical Electronic Warfare Squadron and began its mission from Ubon Royal Thai Air Force Base. The flight crew also were part of the 361st while the collection crew manning the rear of the plane were from Det 3, 6994th Security Squadron. Over Laos, the plane began taking anti-aircraft fire and went down in Salavan Province, Laos about east of the city of Salavan and from the border with South Vietnam at a site in the jungle within of three major roads leading into North Vietnamese-held territory.
Bermuda became important for British Security Co-ordination operations with the ability to vet radio communication and search passengers and mail using flying boats to transit the Atlantic, with over 1,200 people working on opening packages secretly, finding coded messages, secret writing, micro dots and identifying spies working for Nazi Germany, Fascist Italy and Vichy France in the Americas, much of the information found being passed to the FBI. The Island was a base for direction finding equipment to help identify locations of German submarines and took down Enigma encoded messages, which were sent for Cryptanalysis of the Enigma to Bletchley Park. In 1941, the United States signed a lend-lease agreement with the United Kingdom, giving the British surplus U.S. Navy destroyers in exchange for 99-year lease rights to establish naval and air bases in certain British territories. Although not included in this trade, Winston Churchill granted the US similar 99-year leases "freely and without consideration" in both Bermuda and Newfoundland.
FH4 "Huff-duff" equipment on the museum ship High-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency (HF) refers to a radio band that can effectively communicate over long distances; for example, between U-boats and their land-based headquarters. HF/DF was primarily used to catch enemy radios while they transmitted, although it was also used to locate friendly aircraft as a navigation aid. The basic technique remains in use to this day as one of the fundamental disciplines of signals intelligence, although typically incorporated into a larger suite of radio systems and radars instead of being a stand-alone system. HF/DF used a set of antennas to receive the same signal in slightly different locations or angles, and then used those slight differences in the signal to display the bearing to the transmitter on an oscilloscope display.
An airman of the 623rd AC&WS; operates at Point Tare, 1947 Emblem of the 529th AC&W; Gp 1950s 623rd AC&WS; Able Crew Quarters, Camp Bishigawa, Okinawa 1940s Troop Formation, Det 2 623rd AC&WS;, Kume Air Station, Japan, 1950s Re-designated the 623rd Aircraft Control and Warning (AC&W;) Squadron on 2 July 1946, the squadron assumed air direction and control duties of the entire Ryuku Island chain of Japan. It remained in charge of the Okinawa Air Control Center and kept its detachment at Hedo Misake, Okinawa. On 12 October 1946, the 623rd AC&W; Sq sent unit personnel to establish Detachment 2, a Direction Finding (DF) Station on Aguni Shima. By April 1947, the 623rd AC&W; Sq had lost its flight control mission and was concentrating entirely upon air defense of the Ryuku Islands. Detachment 2 at Aguni Shima remained operational for only a short time, and was closed in 30 June 1947.
The ship had a main gun armament of four 4.7 inch (120 mm) QF Mk. IX guns on single mountings, capable of elevating to an angle of 55 degrees rather than the 40 degree of previous War Emergency destroyers, giving improved anti-aircraft capability. The close-in anti-aircraft armament was one Hazemayer stabilised twin mount for the Bofors 40 mm gun and four twin Oerlikon 20 mm cannons. Two quadruple mounts for 21 inch (533 mm) torpedoes were fitted, while the ship had an depth charge outfit of four depth charge mortars and two racks, with a total of 70 charges carried. Swift was fitted with a Type 272 surface warning radar and a high-frequency direction finding (HF/DF) aerial on the ship's tripod foremast, with a Type 291 air warning radar on a pole mast aft and Type 285 fire control radar integrated with the ship's high-angle gun director.
The range of the FuG 7 was approximately 50 km in good weather. Later versions of the FuG 7 included the FuG 7a, which included the S 6a Transmitter, E 5a Receiver and Junction Box VK 5 A. FuG 10 radio panel from a Dornier Do 17 FuG 10 series: A family of transceivers for both R/T and W/T communications. The German FuG 10 panel, or rack, contained two transmitters and two receivers: One transmitter and its companion receiver operated in the MF or Longwave; 300 to 600 kHz (1,000 to 500 m) range and the other transmitter and its companion receiver operated in the HF or Shortwave range; 3 to 6 MHz (100 to 50 m). Most of the FuG 10 series used a fixed wire aerial between the fuselage and tailfin or a retractable trailing aerial wire. The FuG 10P replaced the standard E 10L longwave receiver with an EZ6 unit for a G6 direction finding set.
Chicksands was the site of RAF Chicksands, an RAF signals collection station during and after the Second World War; during the war, it was one of the "Y-Stations" which sent intercepted signals to the Government Code and Cypher School (GC&CS;) at Bletchley Park, where ciphers and codes of several Axis countries were decrypted, most importantly the ciphers generated by the German Enigma and Lorenz machines. The station was used by the United States Air Force from 1950 to 1995, also for signals collection, being the location for its first diameter FLR-9 direction finding antenna, commonly known as the Elephant Cage, from 1963 to 1995. The site was closed as an RAF station in 1997, then handed over to the Intelligence Corps allowing the Corps Headquarters and training delivery to re-locate from Templer Barracks in Ashford, Kent. Channel 4's Time Team visited the base in 2001 and excavated areas in front of and around the priory.
In 1899, Stone resigned from his telephone company position and began to work in Boston as an independent consulting engineer, although he was also retained by his former employer as a "Consultant and Expert in patent causes". His first client was Herman W. Ladd, who was attempting to perfect his "Telelocograph" system for using radio signals as "wireless lighthouses" and for navigational direction-finding. Ladd's approach turned out to be impractical, but the work gave Stone insight about the difficulties facing the embryonic technology of radiotelegraphic signalling, and he recognized that his earlier work on resonant circuits on telephone lines could be applied to improve radio transmitter and receiver designs. Moreover, unlike most other early radio experimenters, Stone had the mathematical background needed to fully analyze electrical circuits. Schematic for four-circuit tuning (1903) In late 1900, the Stone Wireless Telegraphy Syndicate was started in Boston, with an initial funding of $10,000, to do experimental work in devising a commercial system.
On 12 January 1942, Volunteer put to sea from the Clyde with Vanoc, Walker, Witherington, and the destroyer as the local escort of the military convoy WS 15 during its passage of the Northwestern Approaches, detaching on 15 January to return to the Clyde. Similarly, she departed the Clyde on 23 March 1942 with the destroyers , , , , , , and and the escort destroyer as the local escort for the military convoy WS 17 while it transited the Northwestern Approaches during the first leg of its voyage to the Middle East. After Keppel achieved a radio direction-finding fix on the German submarine U-587 on 26 March 1942, the escorts sighted the submarine on the surface and expended all of their depth charges in attacking her after she submerged. Volunteer shared credit with Leamington and the escort destroyers and for sinking U-587 in the North Atlantic west of Ushant at with the loss of her entire crew of 42.
Whitehall continued on Atlantic convoy duty without major incident until April 1943, when she joined Hesperus, Vanessa, corvettes of her escort group, and the 5th Support Group - consisting of the escort aircraft carrier and four destroyers - in escorting Convoy ONS 4. The convoy came under attack by German submarines of Wolfpack Meise. Hesperus sank the submarine , and the escorts damaged other submarines; Whitehall and the corvette pursued a radio direction-finding fix on on 23 April, but were unable to attack because U-732 dived to avoid attack by aircraft from Biter before their arrival on the scene. Syrett, David, The Defeat of the German U-Boats: The Battle of the Atlantic, University of South Carolina, 1994, , pp. 53-54. In May 1943, Whitehall, Hesperus, and ships of the 2nd Escort Group were among eight escorts of the 25-ship Convoy SC 129, which came under attack by 21 German submarines of Wolfpack Elbe on 11 May.
All gear on deck, including the deck crane used to lift the booster frustum on deck, compressors for removing seawater from the boosters, winches and reels, bolt on and off to allow the vessels to be used for purposes other than booster recovery such as towing the Pegasus barge from Michoud Assembly Facility. Communications equipment includes a Kongsberg dynamic position system and joy stick control, X-band and S-band radars for tracking ship traffic and the falling SRBs, global positioning system, handheld VHF radios and GPS units, digital video and recording systems, voice and data satellite communication capability, VHF automatic direction finding, high-frequency single-side band radios, electronic chart plotters, night vision and Sea Area-3 Global Maritime Distress Safety System consoles. To satisfy NASA's need for more observational data during shuttle launches, a Weibel Scientific Continuous Pulse Doppler X-band radar was mounted on MV Liberty Star to provide velocity and motion information about the shuttle and any debris during launch.
Running down the bearing of a HF/DF signal was also used by escort carriers (particularly USS Bogue, operating south of the Azores), sending aircraft along the line of the bearing to force the submarine to submerge by strafing and then attack with depth charges or a FIDO homing torpedo. The British also made extensive use of shore HF/DF stations, to keep convoys updated with positions of U-boats. The radio technology behind direction finding was simple and well understood by both sides, but the technology commonly used before the war used a manually- rotated aerial to fix the direction of the transmitter. This was delicate work, took quite a time to accomplish to any degree of accuracy, and since it only revealed the line along which the transmission originated a single set could not determine if the transmission was from the true direction or its reciprocal 180 degrees in the opposite direction.
The Victorian ARDF Group, a regional ARDF organization in Australia, uses the two-word form of the term radio sport in its logo. Radiosport also can refer to the sport of amateur radio direction finding (ARDF). Although they represent a broad range of amateur radio interests in their nations today, several member societies of the International Amateur Radio Union were originally formed for the promotion and organization of the sport of ARDF and continue to use the term radiosport in their society name. These include the Radio Sport Federation of Armenia, the Belarusian Federation of Radioamateurs and Radiosportsmen, the Chinese Radio Sports Association, the Kazakhstan Federation of Radiosport and Radio Amateur, the Mongolian Radio Sport Federation, All-Russian public radiosport and radioamateur organization «Soyuz Radiolyubiteley Rossii»,Complete name of Russian Amateur Radio Union – SRR, following official charter Ukrainian League of Radio amateurs and the now defunct Radio Sport Federation of the USSR.
The first carrier landing and take-off of a jet aircraft in 1945 Following commissioning, Ocean was sent to Cammell Laird at Birkenhead for modification to operate night fighters - changes included revised radar (with American SM-1 radar replacing the British Type 277 height-finding radar) and improved direction-finding equipment. On completion of these changes in November 1945, Ocean was based at Rosyth for flying trials, with the first trials of the de Havilland Sea Hornet twin- engine fighter and the last carrier operations of the Fairey Swordfish biplane torpedo bomber. On 3 December 1945, a Sea Vampire flown by Eric "Winkle" Brown made the first ever carrier landing of a purely jet-powered aircraft onto Ocean (although earlier that year a composite jet and piston engined Ryan FR-1 Fireball had made a carrier landing under jet power after its radial engine failed.)"First Jet Landing." Naval Aviation News, United States Navy, March 1946, p. 6.
Flow diagram illustrating the Dowding System As the location of No. 11 Group RAF's Operations Room, The Battle of Britain Bunker was one of the key parts of the world's first integrated air defence system. Often known as the "Dowding system" (after Air Chief Marshal Sir Hugh Dowding, Commander-in-Chief Fighter Command at the time of installation), the system linked Fighter Command with Anti-Aircraft Command, Barrage Balloon Command, the Observer Corps, Chain Home Radio Direction Finding (radar), and the intelligence services. Under the system, these organisations worked together for the first time in order to achieve one goal: the successful defence of the UK's airspace. No.11 Group was an important part of the system for several reasons: Firstly, as one of four group headquarters, No.11 Group's Operations Controller was responsible for making key decisions that would affect the outcomes of aerial battles - how many fighter aircraft to scramble, which type of aircraft, which squadrons to use, when to scramble them, where to scramble them from, where to scramble them to, etc.
It also found that the downed Blenheim crews did little to assist the searchers in finding them because the crews engaged in bad direction-finding procedures even after landing and failed to employ visual signals and smudge fires. The inquiry also identified reasons for the early death of the stranded aviators, finding that they failed to appreciate their plight or to ration water immediately and that they made unintelligent use of compass alcohol, having drunk it despite its poisonous qualities, and fire extinguishers, which they had sprayed on themselves for temporary relief from the heat resulting in the infliction of painful skin injuries. To avoid any recurrence of the Kufra incident, the board made comprehensive recommendations with regard to equipment to be carried on aircraft likely to fly over the desert and emergency procedures in the event of forced landings in the desert. It also recommended that only experienced crews operate from Kufra, and that strict procedures be established for operations from Kufra to ensure that aircraft not become lost in the first place and be more easily located if forced down.
Six new direction finding stations were installed as part of these improvements, including one at Lympne. The improvement meant that Croydon would now be able to communicate by radio with two aircraft at the same time. In August Henri Mignet flew his Mignet HM.14 "Flying Flea" across the Channel to Lympne, where the aircraft was demonstrated in front of large crowds. Also that month 601 (County of London) Squadron AuxAF held its annual camp at Lympne after having converted from a bomber squadron to a fighter squadron earlier in the year. From 2 to 16 August 1936, No. 601 Squadron held their annual camp at Lympne. One aircraft exhibited at the 1936 International Air Rally was a 1912 Caudron G.2. In November, it was reported that 21 Squadron and 34 Squadron of the RAF were temporarily relocated to Lympne as hangars at RAF Abbotsinch had been damaged in gales. In October 1936, Lympne was again taken over by the RAF, becoming a base within No. 1 (Bomber) Group.
A two-man team called in a pair of nearby F-16C Fighting Falcons to destroy an Iraqi Army radio direction-finding facility they had identified. A second reconnaissance team from ODA 525 deployed to cover the two highways leading to Ar Rutbah, however as the team was compromised by roving Bedouins who informed the Iraqi Army garrison at Ar Rutbah of the teams presence and location, armed Iraqi technicals crewed by the Fedayeen drove out to search for them, so the Green Berets mounted their GMVs, left their hide and found a position to ambush the Fedayeen, under the weight of fire the Fedayeen retreated. ODA 525 attempted to link up with the two-man reconnaissance team and extract it to safety but large numbers of Iraqi vehicles began driving out of the town to them, the ODAs called in immediate air support. While waiting, the reconnaissance team and Target Acquisition Marines fired on the Fedayeen leaders with their suppressed MK12 sniper rifle and contacted ODA 521 (who were clearing suspects east of the town) and they reinforced ODA 525.
Because of the threat of partisan attacks and the technical difficulties encountered in mountain terrain, Germany was unable to use direction finding. Their employment was unnecessary because any data referring to localities could be obtained through message analysis. The radio traffic of the resistance force subordinated to General Draža Mihailović was observed from the beginning of 1942, first from Athens, later from Belgrade. Radio intelligence provided information on the organisational structure, composition, and concentration areas of this force, also, its plans for future operations, but more often those which had recently been completed, including combat actions, the course of the front lines, shifting of forces, temporary disbanding and subsequent reactivation of combat units; deserters; projected and completed British supply flights, quantities of airdropped supplies, landing fields and their beacon lights; activities of the British and American military missions; behaviours of the Italians and Bulgarians; and finally Mihailović's attitude towards his various enemies, such as the Germans, Milan Nedić, Josip Broz Tito, the Croats, Ustashe, Montenegrins, Albanians and others.
January to May 1943 was spent at HMNB Devonport under refit and conversion as a long range escort; the No.1 boiler (and her forward funnel) was removed to provide space for more fuel tanks and crew quarters; two of her main guns (A and Y) were landed and replaced with a Hedgehog ahead-throwing weapon forward and depth charge stowage and launchers aft; the torpedo tubes were replaced with depth charge stowage and a pair of Oerlikon 20 mm cannon amidships, with a further pair in the bridge wings; the 2-pounders were removed; her gunnery director tower and torpedo control were removed from the bridge to be replaced by an ASDICS control cabinet; she was fitted with Type 144 ASDICS (Sonar), Type 271 target indication radar and Type 291 air warning radar; the latest Wireless telegraphy (W/T), Radio transmitter (R/T) and High- frequency direction finding (H/F D/F) equipment was installed; and Carley rafts were fitted throughout. The effect of removing the boiler was to reduce maximum speed to 27.5 knots, but the increase in fuel increased her range, and her crew complement was raised to 193.
On February 6, 1945, Armig G. Kandoian of New York City was awarded U.S. patent number 2,368,663 (assignor to Federal Telephone and Radio Corporation (later merged with ITT Corporation) for a "broad band antenna", from an application made on May 15, 1943. Excerpt from the Kandoian patent:Patent Application for a Discone Antenna by Armig G. Kodoian > In keeping with progress made during the last few years in the development > of ultra-high frequency radio technique, and applications thereof to > aircraft communication, direction finding, and so forth, it has become > necessary to develop special antennas and antenna systems suitable for > installation on such aircraft. Flying conditions are such that these > antennas must necessarily be small and rigid in their construction and also > offer a minimum of wind resistance, in order that the flying efficiency of > the aircraft will be unimpaired. In accordance with my invention I have > provided a small rigid antenna suitable for mounting on the surface of the > fuselage or other component of the airplane structure and in certain > embodiments I have also provided a streamlined protecting shield or housing > covering or so cooperating with the construction of the antenna system as to > greatly reduce wind resistance.
It resumed base flight operations at Tan Son Nhut in January 1972, operating and maintaining C-47, C-118, and T-39 aircraft. With the 8th Special Operations Squadron (A-37s), the 377th performed strike missions from January through October 1972; the 9th Special Operations Squadron (O-2s and C-47s) conducted psychological warfare operations, January until –February 1972; the 21st Tactical Air Support Squadron (Light) conducted air liaison and forward air control operations from March 1972 until 28 January 1973; the 310th Tactical Airlift Squadron (C/UC-123s, January–June 1972 and C-7s, March–October 1972) performed airlift and airdrop missions until October 1972; the 360th Tactical Electronic Warfare Squadron (C/EC-47s) conducted airborne radio-direction finding operations, February–November 1972, and psychological warfare operations, February–August 1972. The wing established an operating location of the wing headquarters at Bien Hoa Air Base, South Vietnam, on 14 April 1972 to provide turn-around service for McDonnell F-4 Phantom IIs of other organizations. It was replaced on 20 June 1972 by Detachment 1 of the wing headquarters, which continued the F-4 turn- around service and added LTV A-7 Corsair II turn-around service on 30 October 1972.

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