Communications, Radar & Electronic Warfare (201.. - Index of

18Non-CommunicationsElectronic Warfare18.1 Non-Communications EW18.1.1 BroadcastJamming is not just carried out against enemy communications systems, but alsoagainst other types of radio including broadcast systems. Broadcast systems differfrom mobile systems in that the transmission is one way only. The purpose of broadcastjamming is to prevent reception of the victim broadcast transmitter by receivers locatedwithin its service area.Apart from the conceptual difference that the receiver does not transmit, in fact thejamming task is very similar to communications jamming for the mobile case. Theprocess is to determine the received power at each point within the service area and applysuitable jamming power to prevent reception, or to render the output audio or picturesintolerable to subscribers. This is illustrated in Figure 18.1, which shows a directionaljammer jamming part of the coverage area of a broadcast transmitter. Ideally, thecomplete broadcast area should be jammed. This would occur if the limit of jamming issomewhere past the broadcast transmitter as the signal power from the broadcasttransmitter in this direction would rapidly fall offwith distance, makingjamming easier.18. 1.2 Navigation SystemsNavigation jamming, also referred to as navigation warfare, is the process of disruptingreception of navigation signals at certain areas. The purpose can be to deny acceptablereception or to disrupt accurate navigation by providing apparently real signals thatactually result in the receiving platform believing that it is in one location whereas it isactuall y in another.C011117111l11WI1011.\, Radar and Elec1l"Ol11c Warfare© 2011 John Wiley & Sons, LtdAdrIan Graham