Intrusion detection apparatus using leaky cables

摘要

The radiating cable system has parallel metal tubes (1,2,3) spaced apart covering the required zone up to 100 m apart. A transmitter feeds power through a cable (4) to one metal tube (3). A second parallel metal tube (2) is earthed, and a third tube (1) connected to a receive cable (5). The cable is connected to a receiver. A calculator measures the transmit and received power and finds whether a field perturbation from the radiating field has produced an intruder detection.