How Does
How Do Radar Guns Work?
Contributor
By eHow Contributing Writer
Radar
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A radar gun is hand-held device that is used to detect the speed of a moving object. The term "radar" originated as an acronym for radio detection and ranging. Early radar devices were used primarily to locate objects and to determine the relative distance of an object from the radar device. This was accomplished with the use of radio waves. Radar guns work based on the same principles as the original radar devices, but they are used specifically to detect the speed of objects that have been located.
Radio Waves
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Radar guns (and radar in general) work because they have both a radio transmitter and a radio receiver. The radio transmitter in a radar gun sends out radio waves that are directed at a specific object. Once the radio waves hit that object, the waves echo back to the radar gun. Because radio waves always travel at the same speed, the amount of time it takes for the radio waves to return to the radar gun will provide a measurement of the object's distance from the gun.
Moving Objects
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When a radar gun is being used to measure the speed of a moving object, the radio waves that are sent out by the radar gun are echoed back to the gun in a different pattern because the object is moving. So while the speed of the radio waves is the same, they return in a different wave pattern. A radar gun is able to detect the change in the wave pattern and the frequency of wave pattern changes to translate this information into a measurement of speed.
eHow Article: How Do Radar Guns Work?
