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Radar detector

A radar detector is an electronic device used by motorists to determine if their speed is being monitored. The term originates from early speed-detection technologies, in which police bounced a radio wave off a moving vehicle with a device called a radar gun that determined the vehicle's speed by the Doppler-effect-moderated change in the wave's frequency. Most of today's radar detectors detect signals across a variety of wavelength bands - usually X, K, and Ka bands (and Ku, in Europe, also recently approved for use in the U.S).

Newer speed-detection technology uses pulsed laser light (LIDAR, commonly referred to as laser detection) rather than radio waves. Modern "radar detectors" have been adapted to suit that technology, by detecting the infrared light emitted by these new detection methods. LIDAR detection is not nearly as reliable as the detection of radar, since the light is much more focused and often aimed below the windscreen level, where the detector is usually mounted. (The reflective coating of the vehicle licence plate is an excellent laser beam reflector.)

There are many products that are advertised to claim to "scramble" or "absorb" radar; many of these scrambler devices do not work at all, and if they do work, it is by emitting an active radar scrambling pulse, which makes the device illegal to operate under in many jurisdictions.

Despite the advent of LIDAR speed detection, radar remains more prevalent for several reasons, not the least of which are the lower costs of radar (although some insurance companies supply laser guns to police departments for free). Popular radar detector brands include Escort, Valentine One, Beltronics, Whistler, Cobra and K40.

In some countries, using a radar detector is declared illegal and may be subject of fines or seizure of the device. Because the detectors are built around a superheterodyne receiver, and its local oscillator radiates a little, it is possible to build a radar detector-detector which detects such emissions (usually the frequency of the radar they are detecting, plus about 10 MHz) - some police radar guns are equipped with it. But electronic warfare cuts both ways, and the detector detectors use a superhet receiver too, so some radar detectors are equipped with a radar detector detector detector circuit, which shuts down the main radar receiver when the detector detector's signal is sensed, thus preventing being sensed by the police equipment. This problematics is related to technical surveillance countermeasures and ELINT.

See also

• Road safety

External links

• How Stuff Works on Radar Detectors How stuff works on radar detectors.
• Radardetector.co.uk Information about radar and GPS speed camera detectors.
• Radar Detector Summary buyer's guide to popular radar detectors.
• Radar Detector Review Detailed comparison of top performing radar detectors.
• Radar Detector Detector SPECTRE III/STALCAR Radar detector detector manufacturer.
• How Radars Work Detailed information on Australian Radar Detectors and Speed Camera operation.
• 2005 Radar Detector Test & Buyer's Guide Presented by Motor Trend
• Guys of LIDAR Honest & Unbiased Radar Detector and Laser Jammer Tests, conducted by enthusiasts.
• Radar Test Enthusiast's guide to detectors, mobile electronics, cool cars and must-have gadgets.
• Radar Busters - expert reviews by a retired police officer on radar detectors, jammers, and other such products.

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This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.