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The radial wires either may run above the surface of the earth (elevated radials), on the surface (on ground radials), or buried a centimeter or so under the earth (buried radials). The ends of the wires nearest the antenna base are connected to the antenna system electrical ground, and the far ends are either unconnected, or connected to metal ...
It consists of a network of radial copper wires suspended above the ground, connected to the transmitter feedline ground. It is suspended about 8 feet above ground, so technicians can get access to the helix house at the foot of the tower. Antenna used in Lodge-Muirhead wireless system around 1900, the first counterpoise.
The other terminal of the transmitter is connected to a radial ground system consisting of cables buried under the field. A monopole antenna is a class of radio antenna consisting of a straight rod-shaped conductor, often mounted perpendicularly over some type of conductive surface, called a ground plane.
Antenna reactance may be removed using lumped elements, such as capacitors or inductors in the main path of current traversing the antenna, often near the feedpoint, or by incorporating capacitive or inductive structures into the conducting body of the antenna to cancel the feedpoint reactance – such as open-ended "spoke" radial wires, or ...
Buried in the ground under the antenna is an enormous radial ground system, which forms the bottom 'plate' of the capacitor with the overhead top load. The antenna must be very large at the VLF frequencies used; the supporting masts are 250–300 metres (820–980 ft) high, and the topload is about 1,900 metres (6,200 ft) in diameter.
In most antennas, the radiation from the different parts of the antenna interferes at some angles; the radiation pattern of the antenna can be considered an interference pattern. This results in minimum or zero radiation at certain angles where the radio waves from the different parts arrive out of phase , and local maxima of radiation at other ...
Omnidirectional radiation patterns are produced by the simplest practical antennas, monopole and dipole antennas, consisting of one or two straight rod conductors on a common axis. Antenna gain (G) is defined as antenna efficiency (e) multiplied by antenna directivity (D) which is expressed mathematically as: =.
Height above average terrain (HAAT), or (less popularly) effective height above average terrain (EHAAT), is the vertical position of an antenna site above the surrounding landscape. HAAT is used extensively in FM radio and television , as it is more important than effective radiated power (ERP) in determining the range of broadcasts ( VHF and ...