136. To shoot or to spot?

A Radar Gun is used to detect the speed of moving objects and vehicles. Though it does not pinpoint the position of the object, it can measure the speed of the object very accurately.

The Radar Gun was first invented by Bryce .K. Brown, in March 1954. It came into use almost immediately in April 1954!

A Radar Gun works on the principle of “Doppler Effect”. You must have noticed that the whistle of a train or the sound of the horn of a car, become sharper as they approach us and become flatter when they recede. This is the Doppler Effect, which studies the shift in the frequency of the waves due to motion.

A Radar Gun is in fact a radio transmitter cum receiver. It can send out and receive radio signals, as they get scattered by the moving objects. The reflected signal is different from the transmitted signal. This difference or “the shift” is used to calculate the speed of the objects.

A Radar Gun must be stationary to measure the speed. In a moving Radar, the frequency shift between the various images is compared and used to calculate the speeds.

All bands of radar work on the same principles, but on different frequencies namely X, K, Ka and Ku bands. There are different models, hand-held, stationary and moving. Hand-held models are battery operated. Stationary models, with one or two antennas, are fitted on parked vehicles. Moving radars are Hi-fi and can track the speeding vehicles in the front as well in the rear!

With the advance of science, the fast drivers now have at their services, “Radar Detector,” which can detect police radar in action, and warn them!

Not to be left out of the rat-race, the policemen have come up with a more complex tool to help them—“The Detector of (an operating) radar detector”! How do you like it??

Visalakshi Ramani