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How Do Radar Detectors Work?

Posted on July 7, 2019 by Harold Weier

Authorities have used radars to monitor the speed of motorists and to help maintain safe streets. Meanwhile, many drivers have started using radar detectors to help avoid costly fines for speeding violations. Regardless of the prevalence of radars and radar sensors, a lot of folks don't understand the technology or science behind them.

Police radar guns work by transmitting radio waves from the radar to the target vehicle and rear. Since radio waves move through the atmosphere at a constant speed (the speed of light), radars can calculate how far away an object is based upon how long it takes to the radio signal to return. When an object such as a car is moving, there's a change in frequency from the radio waves. Radars detect this change and convert it into miles per hour to ascertain the target's speed. Further, radar guns also use various kinds of bands to ascertain the target's speed, such as X band, K band, and Ka band. Classic radar sensors alert the driver to the presence of radars.

Law enforcement officers use lasers (concentrated mild ) to determine a vehicle's speed. Laser radar guns measure the time it requires infrared light to leave its source, reach a vehicle, bounce off, and return. These tools can determine how far away an object is by multiplying this time by the speed of light. Because this sort of radar sends out many bursts of light to determine many distances, the system can determine how fast the vehicle is moving by comparing these samples. But as laser speed detectors have a much more focused beam and discover lasers over great distances, police laser guns are normally more challenging to evade. While modern radar sensors often incorporate a light-sensitive panel that finds these light beams, the sensor (and thus vehicle) is usually already in the beam's sights.

While conventional sensors worked by alerting the driver to the presence of the laser or radar, the past few years have seen a increase in radars which also emit a jamming signal. This sign duplicates the original sign from the police radar gun and combines it with additional radio sound, which confuses the radar receiver, and prevents the police officer from avoiding an accurate speed reading. Some sensors also use a laser jammer, or light emitting diodes (LEDs), that produce a light beam of their own. This beam prevents the recipient from recognizing any reflected light to get a clear reading on the car's speed.