Fractal filters (a type of tuned circuit) are another example where the superiority of the fractal approach for smaller size and better rejection has been proven. As fractals can be used as counterpoises, loads, ground planes, and filters, all parts that can be integrated with antennas, they are considered parts of some antenna systems and thus are discussed in the context of fractal antennas.
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In addition to their use as antennas, fractals have also found application in other antenna system components including loads, counterpoises, and ground planes. Fractal inductors and fractal tuned circuits (fractal resonators) were also discovered and invented simultaneously with fractal element antennas. An emerging example of such is in metamaterials. A recent invention demonstrates using close-packed fractal resonators to make the first wideband metamaterial invisibility cloak at microwave frequencies.
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Inverted-L antenna with counterpoise, in a powerful amateur radio station, Colorado, 1920. The counterpoise is the lower grid of horizontal wires, suspended below the antenna. The largest use of counterpoises is in transmitters on the low frequency (LF) and very low frequency (VLF) bands, as they are very sensitive to ground resistance. Because of the large wavelength of the radio waves, feasible antennas used at these frequencies are electrically short, their length is a small fraction of the wavelength.
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The novel counterpoises the spiritual power of the shaman with the political power of the Czar. The absolute power of the Czar and the prevalence of slavery in the land are represented as productive of evil. The Czar's power is shown to be on uncertain ground; although he has the power of life and death over others, he is ruled by his fear of losing his Czardom. The shaman, however, whose power is based on knowledge, lives free, walks invisible, and is all but invulnerable to harm.
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Counterpoises are typically used in antenna systems for radio transmitters where a good earth ground connection cannot be constructed. Monopole antennas used at low frequencies, such as the mast radiator antennas used for AM broadcasting, require the radio transmitter to be electrically connected to the Earth under the antenna; this is called a ground (or earth). The ground must have a low electrical resistance, because any resistance in the ground connection will dissipate power from the transmitter. Low-resistance grounds for radio transmitters are normally constructed of a network of cables buried in the earth.
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Tefnut is a leonine deity, and appears as human with a lioness head when depicted as part of the Great Ennead of Heliopolis. The other frequent depiction is as a lioness, but Tefnut can also be depicted as fully human. In her fully or semi anthropomorphic form, she is depicted wearing a wig, topped either with a uraeus serpent, or a uraeus and solar disk, and she is sometimes depicted as a lion headed serpent. Her face is sometimes used in a double headed form with that of her brother Shu on collar counterpoises.
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4(Z),7(Z),10(Z),13(Z),16(Z),19(Z)-docosahexaenoic acid (DHA) is metabolized by the same CYP epoxygenases that metabolize arachidonic acid to form epoxide-containing docosapentaenoic acid products, particularly 19,20-epoxy-4(Z),7(Z),10(Z),13(Z),16(Z)-docosapentenoic acid. These docosapentaenoic acid epoxides or Epoxydocosapentaenoic acids (EDPs) have a somewhat different set of activities than, and thereby may serve in part as counterpoises to, the EET's; EDPs may also be responsible for some the beneficial effects attributed to omega-6 fatty acid-rich foods such as fish oil (see Epoxydocosapentaenoic acid).
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Another source of resistance is dielectric losses from the penetration of radio waves into the ground near the antenna due to the large skin depth at low frequencies. Therefore, particularly at VLF frequencies, large counterpoises are often used instead of buried grounds, to reduce the ground system resistance, allowing more of the transmitter power to be radiated. Sometimes a counterpoise is combined with an ordinary ground, with the buried radial ground cables brought above ground near the base of the antenna to form a counterpoise. The area of the counterpoise around the base of the antenna is often covered with copper screening, to shield the ground to reduce ground currents.
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Usually the metal mast itself is used as the antenna, and is mounted on a large porcelain insulator to isolate it from the ground; this is called a mast radiator. The monopole antenna, particularly if electrically short requires a good, low resistance Earth ground connection for efficiency, since the ground resistance is in series with the antenna and consumes transmitter power. Commercial radio stations use a ground system consisting of many heavy copper cables, buried a few feet in the earth, radiating from the base of the antenna to a distance of about a quarter wavelength. In areas of rocky or sandy soil where the ground conductivity is poor, above ground counterpoises are used.
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