The use of remote equipment overcomes some of these problems. It allows the
antenna to be positioned in an operationally correct site while the radio is
operated from a well concealed command post area. Field radio communication
will always be better if a few simple rules for siting antennas are
consistently applied. They are as follows:
Locate the antenna high enough to overlook the surrounding terrain.
(Always keep line of sight in mind.)
Keep the antenna clear of brush and tree branches.
(Foliage
touching antenna elements may ground the antenna.)
In a clearing, locate the antenna on the edge farthest from the
distant station.
(Ideally, the clearing should extend 100 meters
from the antenna in the direction of the distant station.)
Keep antenna joints, transmission lines, and coupling connectors
free of dirt, water, and snow.
Orient a directional antenna in a straight path to the receiving
station.
(If the straight path is masked or obstructed, a slight
off-path course may be used.)
In mountainous terrain, use valleys and gaps as transmission paths.
Use an adequate counterpoise,
especially
in
desert
areas
where
ground conduction is poor.
If you have trouble reaching a distant station, move the antenna a
short distance and try again.
(Even a small movement may cancel
what is affecting your transmission.)
Use a retransmission station.
11. ANTENNA AT-984A/G. The fire support team (FIST) depends primarily on
the low-power FM radio AN/PRC-77 as its link with the firing unit(s).
Because of the limited range capabilities of this radio, siting of the radio
set antenna is critical.
To increase communication range, tables of
organization and equipment (TOE) changes have added the long-wire,
bidirectional antenna AT-984A/G to FIST communication equipment.
a. Description.
Antenna AT-984A/G (Fig 12) is a long-wire, end-fed,
directional antenna that is used to extend the communication distance of FM
tactical radio sets operating in the 30.00 to 76.00 MHz range.
It is
primarily used with the radio set AN/PRC-77, but can be used with the
AN/VRC-12 series of radios when a highly directional antenna is required.
b. Components. The antenna AT-984A/G consists of a wire reel
and 150
feet of antenna wire carried in a canvas bag (Fig 12). The antenna
wire is
terminated on one end with a copper terminal lug. The bag has two
locking
devices which can be attached to the belt, thus leaving both hands
free to
install the antenna.
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