High Quality Content by WIKIPEDIA articles! A radar speed gun (also radar gun and speed gun) is a small doppler radar unit used to measure the speed of moving objects, including vehicles, pitched baseballs, runners and other moving objects. Radar speed guns may be hand-held, vehicle-mounted or static. A radar speed gun measures the speed of objects at which it is pointed by detecting a change in frequency of the returned radar signal due to the Doppler effect. Modern radar speed guns normally operate at X, K, Ka, IR Band (infrared), and (in Europe) Ku bands.