Figure 70.
Tying the whip antenna down.
6.
Long-Wire Antennas.
a. Long-wire antennas are antennas that are longer than a half-
wave in length.
There are two advantages that a long-wire antenna
has over a half-wave antenna: directivity and gain.
In our
discussion of long-wire antennas, the focus will be on practical
antennas for VHF (30 -300 MHz) applications.
Antennas that are
several wavelengths long are not practical for tactical HF (3 to 30
MHz) communications.
Antennas several wavelengths long at HF
frequencies would be several hundred feet in length.
b. Antenna gain.
Antennas discussed previously develop no gain
in any particular direction.
They either radiate in all directions
or radiate in two directions only.
A point can be made that a
horizontal antenna has gain as compared to a vertical antenna. Power
to a vertical antenna goes in all directions, while power to a
horizontal antenna goes in two directions.
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