_______________________________________________________________________ Antennas
4-86. As explained earlier, ground losses affect radiation patterns and cause
high signal losses for some frequencies. Such losses may be greatly reduced if a
perfectly conducting ground is provided in the vicinity of the antenna. This is
the purpose of a ground screen (figure 4-20, view A) and counterpoise (view B).
Figure 4-20. Ground Screen and Counterpoise
4-87. The ground screen in figure 4-20, view A is composed of a series of
conductors buried 1 to 2 feet (0.3 to 0.6 meter) below the surface of the earth
and arranged in a radial pattern. These conductors reduce losses in the
ground in the immediate vicinity of the antenna. Such a radial system of
conductors is usually one-half wavelength in diameter.
4-88. A counterpoise, as shown in figure 4-20, view B, is used when easy
access to the base of the antenna is necessary. It is also used when the earth
is not a good conducting surface, such as ground that is sandy or solid rock.
The counterpoise serves the same purpose as the ground screen but it is
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