Type of modulation (AN or FM).
Tactical FM radio equipment
requires a 50-KC band for each channel (older sets require
100-KC channels); AM equipment requires a 10-KC band for each
Ensure that the separation between adjacent FM
channels is proportionately greater than the separation
between adjacent AM channels.
transmitter often has a tendency to change or drift.
reduce inefficiency caused by an off-frequency operation,
ensure that most field radio stations maintain an accuracy of
0.01 percent of the assigned frequency.
For example, an
assignment of 4,000 KC (4,000,000 cycles), with a tolerance of
cycles above or below the assigned frequency.
obviously affects the amount of separation between adjacent
Power output of transmitter.
The transmission distance and
related to its rated power output. A high-powered transmitter
sufficient separation in operating frequencies.
reason, the use of minimum power output consistent with
satisfactory communication is often stipulated in the SOP.
Distance separation between different nets.
A radio signal,
when received at a distant station, may occupy only a few KCs
on the receiver dial. When received on a nearby receiver, the
same signal will normally occupy a much broader band of
frequencies. Since adjacent channel interference occurs more
readily when stations are located close together, provide a
relatively large separation between operating frequencies
assigned to different net stations located at the same command
The various factors listed above indicate that the amount of
separation between operating frequencies can vary.
To conserve the
by referring to the short distance ground and sky-wave prediction
charts, which are published every three months in the command SOI.
The army signal officer can provide you with these charts.