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A whip antenna with several rods extending horizontally from base of the whip in a star-shaped pattern, similar to an upside-down radiate crown, that form the artificial, elevated ground plane that gives the antenna its name. The ground plane rods attach to the ground wire of the feedline, the other wire feeds the whip. Since the whip is ...
For a monopole antenna (a), the Earth acts as a ground plane to reflect radio waves directed downwards, making them seem to come from a virtual "image antenna" (b).In Telecommunications, a ground plane is a flat or nearly flat horizontal conducting surface that serves as part of an antenna, to reflect the radio waves from the other antenna elements.
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, below 3 MHz, 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).
Since the circuit board ground is often smaller than the antenna, the antenna and ground combination may function more as an asymmetrical dipole antenna than a monopole. The hand and body of the person holding them may function as a rudimentary ground plane. Wireless devices and cell phones use a monopole variant called the inverted-F antenna. [15]
Today, HFDL is an air/ground data link standard with coverage in virtually every corner of the globe, approximately 168,000,000 square miles (440,000,000 km 2) where aircraft are never out of touch both in the air and on the ground. There are around 15 HF ground stations (HGS) available today, and, like a canopy within a jungle, the stations ...
When an actual ground is not available (such as in a vehicle) other metallic surfaces can serve as a ground plane (typically the vehicle's roof). Alternatively, radial wires placed at the base of the antenna can form a ground plane. For VHF and UHF bands, the radiating and ground plane elements can be constructed from rigid rods or tubes.
Whips mounted on vehicles use the metal skin of the vehicle as a ground plane. In hand-held devices usually no explicit ground plane is provided, and the ground side of the antenna's feed line is just connected to the ground (common) on the device's circuit board. [2] Therefore, the radio itself serves as a rudimentary ground plane.
To prevent interference with these services, amateur and experimental transmitters were restricted to the high frequencies (HF), felt to be useless since their ground-wave range was limited. Upon discovery of the other propagation modes possible at medium wave and short wave frequencies, the advantages of HF for commercial and military purposes ...
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