Meaconing, Intrusion, Jamming, and Interference (MIJI)

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.