4.
Multichannel
Techniques.
Commander
use
line-of-sight
(LOS)
multichannel communication radio, troposcatter, and satellite relay.
a. Common myths about the security of multichannel communications can
cause operators to violate basic COMSEC practices.
(1) Many think a multichannel radio is
always secure.
Many also
think multichannel radio signals can only be
intercepted from positions
forward of the sending directional antenna, or
within or on the immediate
fringes of areas the signal beam spans, or from
forward of the transmission
path. However, these notions are no true.
(2) Multichannel radio signals can be intercepted by very accurate
enemy sensors.
However, multichannel does have some defensive EW
characteristics.
At a signal site, individual subscriber's circuits are
assigned to a particular channel and electronically superimposed onto one
carrier frequency and transmitted using one radio.
In addition, the LOS
radiation pattern is narrow and directional, instead of omni-directional.
Also, each channel is secured, using a crypto-secure device.
b. Too many operators use the nonsecure orderwire to discuss classified
matters.
Examples are movement time, locations, and other operations-
related information.
Use the orderwire only for systems and circuit
alignment. Also set up a separate engineering channel for operators.
c. Operating with misconceptions causes preventive ECCM techniques to
have limited value. An enemy's successful penetration of multichannel nets
allows him to focus his attention on carefully guarded information. Do not
be the one who leaks information.
PART B - REMEDIAL MEASURES
1.
Remedial Electronic Counter-Countermeasures. These are actions taken
in response to enemy jamming.
Remedial ECCM techniques reduce the
effectiveness of enemy jamming efforts (Figure 2-1, page 2-8).
These
techniques apply to jamming and unidentified or unintentional interference
that disrupts friendly communications.
Remedial ECCM techniques do not
apply
to
other
actions
that
might
disrupt
or
destroy
friendly
communications.
a. Jamming may be either obvious to the operator or extremely subtle
and difficult to detect. An enemy may use modulated or unmodulated signals.
He may use spot, barrage, or sweep jamming. Spot jamming directs the jammer
signal against a single frequency.
Barrage jamming directs the jamming
signal against a frequency band, disrupting many frequencies. Sweep jamming
directs the jamming signal up and down a frequency band; it does not lock
onto a specific frequency or group of frequencies.
2-7
SS0135
Previous Page
