normal manner, as before the jamming an enemy may assume his jamming was not
very effective. If he finds us excitedly discussing our problem on the air,
an enemy may assume his jamming was effective. He may also think so if we
shut down our operation. There is a rule that applies when being jammed.
Unless otherwise ordered, never shut down operations or in any other way
disclose to an enemy that you are being adversely affected.
This means
normal operations continue, even when degraded by jamming.
b. Improve the signal-to-jamming ratio.
This involves the relative
strength of the desired signal to the jamming signal at the receiver.
Signal refers to the communications or emission received. Jamming refers to
the hostile or unidentified interference being received.
Try to have a
signal-to-jamming ratio where the desired signal is stronger than the
jamming signal. Then, the desired signal cannot be significantly degraded
by the jamming signal. The following helps to improve the signal-to-jamming
ratio:
(1) Adjust the receiver. When jamming is experienced, check to make
sure the receiver is tuned as precisely as possible to the desired incoming
signal. A slight receiver readjustment may provide an improved signal-to-
jamming ratio. Specific methods that apply to a certain radio are in the
operator's manual. Some of these methods are:
(a) Adjust the beat frequency oscillator.
(b) Adjust the bandwidth.
(c) Adjust the gain or volume control.
(d) Fine-tune the frequency.
(2) Increase the transmitter power output. The most obvious way to
improve the signal-to-jamming ratio is to increase the transmitter's power
output. To increase power output during jamming, the transmitter must be on
less than full power when jamming begins. Using low power as a preventive
technique depends on the enemy not being able to detect our radio
transmissions.
Once the enemy begins jamming our radios, the threat of
being detected is moot. Use the reserve power on terrestrial, line-of-sight
(LOS) radios to override an enemy's jamming signal.
Tactical satellite
communications terminals will not increase their transmit power.
(3) Adjust or change the antenna.
Adjustments can improve the
signal-to-jamming ratio.
When being jammed, make sure the antenna is
optimally adjusted to receive the desired incoming signal. Specific anti-
jamming methods used for a radio set are found in the operator's manual.
Some methods are:
(a) Reorient the antenna.
(b) Change
the
antenna
(must
be
done
by
all
stations).
(c) Install an antenna with a longer range.
SS0135
3-6
Previous Page
