Heavily promoted radar jammers, with money-back guarantees to pay speeding fines incurred while using them, are as effective at hiding excessive speeds from a police radar detector as a block of wood, researchers report. Responding to claims by a number of devices ranging in cost from $150 to $300, they ran a car past expert police radar operators at speeds ranging from 32 mph to 50 mph with the devices turned on and off, and the police could detect no difference with or without the jammers: the car's speed was reliably and accurately recorded each time. Makers claim that an "FM chirp, a mixer and an antenna" interfere with the radar device and render it blank. They also say that the jammers do not have any effect on the roadside speed detection signs because they don't have a "sampling computer." Safety experts worry that drivers will be encouraged to speed if they operate the jammers and believe they can this escape detection and sanctions. (Author/publisher)
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