2. Antenna orientation is not a consideration for short distance sky
wave use. If possible, use a radial ground system, especially with a
whip, using 36 radials which should be as long as the antenna.
Sometimes a radial system makes communication worse when it is
connected to the equipment ground.
To be sure, always try to
communicate first without the radial ground connected to the
equipment ground, then with it.
3. From a signal security standpoint, we are in trouble. In order
to increase the reliability of the whip, we use higher frequencies
which provide the enemy with a better opportunity to monitor and jam
our signal.
Most of the time, if we use a whip, we must sacrifice
signal security in order to maintain the radio circuit. If we use a
doublet, we could use the LUF which makes monitoring and jamming more
difficult.
During displacement, communications is very crucial but
also marginal in reliability if we use a whip.
We must therefore
make a compromise and ease our signal security concerns in order to
increase the reliability of the radio circuit by using the whip's
LUF.
With 100 nets requiring the same FOT/LUF, obviously not all
nets can use the same LUF or FOT.
More compromises are necessary.
Frequency assignments will be close as possible to the FOT down to
the whip's LUF.
4. Usually, most of our units communicate less than 50 miles (closer
to 5 - 25 miles).
One consideration to make is the use of ground
waves for short distance radio circuits. Let us compare some charts
for various antennas.
Look at the ground wave charts, page 156 to
page 161, especially for a 15-foot whip (use column 7). Notice that
if we use any frequency from 12 -25 MHz, a ground wave will meet our
circuit path requirements of 25 miles.
Ground Wave Range (p 159)
Ground Wave for 32-Foot Whip
At 0200 Hours (p 160)
For 15-Foot Whip
At 0200 Hours For
Column 7 (300 to 499
Watts) For RTTY 60
WPM (p 158)
02 Hours
(7)
(7)
15-Ft
32-Ft
Whip
Whip
2
MHz
9.0
27
3
MHz
14
28
5
MHz
17
29
7
MHz
20
32
10
MHz
24
33
12
MHz
25
33
15
MHz
26
33
20
MHz
26
32
25
MHz
25
6.8
30
MHz
24
2.4
119
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