procedure: A radar gun uses the Doppler Effect to detect the speed of objects. It transmits electromagnetic waves, which bounce off the object it is pointed at, returning to the device at a slightly different frequency. The radar detects the change in frequency, then computes this into a speed measurement. The radar can be set to record peak velocity, of either an object such as a ball, or the arm or bat, which is handy for many sports. The radar can be hand-held or one that can be placed on a tripod or on the ground. To get correct speed gun readings most radar guns will need to be placed directly in the line of travel of the object to be clocked, otherwise only a component of the true speed will be measured.
target population: radar can be used to measure running speed in sprinters, throwing speed in sports such as baseball, cricket, softball, and in hitting sports such as Tennis (serve speed) and golf (swing speed) and hockey. You may also be able to measure punching hand speed in boxing.
limitations: A radar gun does not return information regarding the object's position. Peak speed will only be measured if the radar is placed directly in line of the moving object.
accuracy: The resolution of each radar may vary, ranging from +/-0.1 mph to +/- 1.0 mph. The accuracy is difficult to determine, as it would require you to find a object of known speed to calibrate against.
range: The radar will vary in how far away you can use the instrument. Some will be able to measure a moving object from a mile away.
comments: Radar is an acronym for RAdio Detection and Ranging. It was invented by Bryce K. Brown of Decatur Electronics in March 1954.