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TM 9-2320-356-BD
11. If there is a BNC connector (twist-lock) on the cable, attach it to the radio
antenna connector.
If not, prepare and connect the coaxial cable as follows:
a.
Carefully strip the outer insulation from the coaxial cable to expose enough
braided shield to reach a screw near the antenna connector on the radio case. Do
not cut shielding.
b.
Use a pencil or nail and carefully separate the braided shield from around
the center conductor insulation.
c.
Twist shield wire into a pigtail.
d.
Strip the center conductor insulation to expose enough wire to push into the
antenna connector.
e.
Wedge the wire into the center of the antenna connector.
f .
Attach the pigtail to a screw on the radio case.
12. Record BDAR action taken.
When the mission is complete, as soon as
practicable,
repair using standard maintenance procedures.
15-9.
TRANSMISSION ANTENNA SUBSTITUTES
General Information:
This procedure gives instructions for making a 1/4 wave ground plane antenna, long
wire antenna, or a half rhombic antenna.
The transmission range is greatly
increased but cannot be used during mobile operations.
The length of the 1/4 wave
ground plane antenna elements must be selected because a matching unit will not be
used.
For quick reference, wire lengths for the following frequencies are given
for each leg of the completed antenna:
a.
30.00 MHz (MC) = 7 ft 9 in.,
b.
40.00 MHz (MC) = 5 ft 8 in.,
c.
50.00 MHz (MC) = 5 ft 0 in.,
d.
60.00 MHz (MC) = 3 ft 11 in., and
e.
70.00 MHz (MC) = 3 ft 4 in..
For best performance, the exact wire length for each frequency to be used can be
calculated using this formula:
length (feet) = 234 divided by the frequency in MHz
(MC).
Limitations:
o Not for mobile use
o Long wire and half rhombic antennas are very directional
o Must build a new antenna for every 10.00 MHz frequency change
15-9
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