Jamming of Communication Systems Using FM, AM, and SSB Modulation

Abstract

Jamming of voice communication systems is a very ungrateful task and ``brute force'' jammers have to be used, while other systems, such as radar, can be jammed effectively using low power but sophisticated jammers. Geographical situation is very much against the jammer, particularly in ground-based mobile communication systems. The propagation of ground wave is such that a rapid increase of jamming power is required, as the ratio of distances of the jammer to the desired transmitter increases. The jammer is never certain whether or not the communication network is jammed and is never actually able to jam the communications completely. It can only limit the operating range of the system. Different modulation systems are considered and the necessary power density for jamming of each system is discussed. It is concluded that effective jamming of FM systems and other systems with threshold systems is easier than that of AM and, particularly, the SSB systems. However, for nuisance jamming, the opposite is true. Finally, the jamming of the SSB systems is considered in more detail and it is proven that the so-called reduced-carrier SSB systems are not easier to jam than systems with a completely suppressed carrier.