A radar speed meter operating on doppler principle has been designed and fabricated to measure the speed of vehicles plying on the roads. It comprises of a 2K 25 klystron as a transmitter, a waveguide type leaky wave antenna radiating energy in a beam of 8° in azimuth at 20° to the length of the waveguide which is aligned parallel to the road. The received echo from the moving vehicle crossing the beam is separated by a hybrid T and fed to a detector which is already receiving the reference signal. The doppler output is amplified, limited and is used to drive a multivibrator. The resultant train of pulses is counted by a frequency sensitive network, and the output voltage calibrated in speed is displayed on a meter. The whole unit is mobile and works on car battery. It can measure speeds from 10 to 100 km/hr ± 2 km/hr. Error in speed measurement is not appreciable with ±2° misalignment of the antenna.
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