A station transmits operating instructions that
affect communications, such as closing down a
station, shifting frequency, or establishing a
special circuit.
You can find further information on authentication
in Communications Instructions—Security (U), ACP
122.
MEACONING, INTRUSION, JAMMING,
AND INTERFERENCE (MIJI)
MIJI is a term used to describe four types of
interference that you are likely to experience in a given
situation.
Meaconing is the interception and rebroadcast of
navigation signals. These signals are rebroadcast on the
received frequency to confuse enemy navigation.
Consequently, aircraft or ground stations are given
inaccurate bearings. Meaconing is more of a concern
to personnel in navigation ratings than to you as a
Radioman. However, communications transmitters are
often used to transmit navigation signals. Since
communications personnel operate the transmitters,
they must know how to deal with any communications
problems resulting from meaconing.
Intrusion is defined as any attempt by an enemy to
enter U.S. or allied communications systems and
simulate our traffic to confuse and deceive. An
example of intrusion is an unauthorized radio
transmission by an unfriendly source pretending to be
part of an air traffic control service and giving false
instructions to a pilot.
Jamming is the deliberate radiation, reradiation, or
reflection of electromagnetic signals to disrupt enemy
use of electronic devices, equipment, or systems. In
jamming operations, the signals produced are intended
to obliterate or obscure the signals that an enemy is
attempting to receive. Some common forms of
jamming include:
l
l
l
l
l
Several carriers adjusted to the victim frequency;
Random noise amplitude-modulated carriers;
Simulated traffic handling on the victim
frequency;
Random noise frequency-modulated carriers;
Continuous-wave carrier (keyed or steady); and
3-12
Several audio tones used in rapid sequence to
amplitude modulate a carrier (called bagpipe
from its characteristic sound).
Interference is normally a nondeliberate intrusion
upon a circuit. It unintentionally degrades, disrupts,
obstructs, or limits the effective performance of
electronic or electrical equipment. Interference usually
results from spurious emissions and responses or from
intermodulation products. Sometimes, however,
interference may be induced intentionally, as in some
forms of electronic warfare. An example of
interference is the interruption of military transmissions
by a civilian radio broadcast.
The more effective methods of dealing with MIJI
are contained in Fleet Communications, NTP 4, and in
Reporting Meaconing, Intrusion, Jamming, and
Inteference of Electromagnetic Systems, OPNAVINST
3430.18.
SUMMARY
In this chapter we introduced you to the basic
concepts of communications security, described
various cryptosystems, and familiarized you with the
procedures and methods of transmission security.
As a Radioman, you have a two-fold job concerning
security. The first, of course, is to properly perform
your duties within general security guidelines. Security
guidelines pertain to everyone in every official capacity.
Second, you must also perform your duties in such a
manner as to protect the integrity and overall value of
secure communications.
Security violations result from bad personal habits,
security indifference, occupational fatigue, or
ignorance of established regulations. When security
violations occur in installations located in foreign
countries, the violations become more serious because
of an activity’s greater vulnerability to hostile
exploitation. With respect to COMSEC, security
violations could prove costly.
Security precautions mentioned in this chapter do
not guarantee complete protection, nor do they attempt
to meet every conceivable situation. Anyone who
adopts a commonsense outlook can, however, solve
most security problems and gain a knowledge of basic
security regulations. For information on local security
rules, study your command’s security regulations.
