Radar detectors or fuzz busters are electronic devices used by motorists to determine if they are being tracked or their speed is being motorized by a radar unit. Police use a radio wave and bounce it off of a moving object or most likely a vehicle if this is the case. It determines the speed of the vehicle by the Doppler-effect-moderated change in the wave’s frequency since most radar detectors today detects signals across a variety of wavelength bands. This is also the same device being used by car racers to measure the speed of a car in a distance.

The concept is very simple. The radar measures the speed of a vehicle or anything that is in a distance. The radar has a radio transmitter and a receiver combined, thus making the measurement very accurate.

A radio transmitter is a simple device that swings the electrical current so the voltage goes up and down at a certain amount of frequency. The electricity then produces electromagnetic energy, so when the current swings, the energy that travels through the air as an electromagnetic wave is received. The radio transmitter also has an amplifier that increases the intensity of the electromagnetic energy and an antenna that broadcasts it into the air.

A radio receiver on the other hand is just the exact opposite of the radio transmitter. As its name states, the radio receiver receives electromagnetic waves with its antenna and converts them back into an electrical current.

The radar uses the radio waves to detect and monitor different objects. The simplest function of it is the measurement of how far the object is. It measures the distance, some measures the speed as well, as have said. The radar emits a concentrated radio wave and records the echo it produces. If there is an object in the path of the radio waves emitted, the radio waves would reflect and bounce back some of its electromagnetic energy.

Radio waves move through the air at a constant speed of light. The radar device then calculates how far the object is based on how long it takes the radio signal to return to the radar device. It is the same as the tapping of rod by a blind man. Aside from warning for near objects, the rod produces a sound that gives the blind man the idea if there is an object or something around him. This is also the reason why blind people have better sense of hearing.

The problem with this Doppler effect in measuring how far the subject is when the object is moving. Take for example, a vehicle and the police holding the radar. Once the police pulls the trigger of the radar and tries to measure the distance, by the time he receives the measurement, the distance has already changed. Well, of course, policemen do not measure distance, they measure speed.