Radar detector detector
A radar detector detector (RDD) is a device used by police or law enforcement in areas where radar detectors are declared illegal. Radar detectors are built around a superheterodyne receiver, which has a local oscillator that radiates slightly. It is therefore possible to build a radar-detector detector, which detects such emissions (usually the frequency of the radar type being detected, plus about 10 MHz for the intermediate frequency). Some radar guns are equipped with such a device. However, like any device that detects stray emissions from electronic equipment, it is easily defeated by using adequate shielding. History The VG-2 Interceptor was the first device developed for this purpose, although more current technology such as the Spectre III (Stalcar in Australia) is now available. This form of "electronic warfare" cuts both ways and since detector-detectors use a similar superheterodyne receiver, many early "stealth" radar detectors were equipped with a radar-detector-detector-detector circuit, which shuts down the main radar receiver when the detector-detector's signal is detected, thus preventing detection by such equipment. In the early 1990s, BEL-Tronics, Inc. of Ontario, Canada (where radar detector use is prohibited) found that the local oscillator frequency of the detector could be altered to be out of