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Abstract
A radio telemetering system operating at 400 MHz has been described. It has been installed at the Bombay harbour for measuring the amplitude and frequencies of sea waves over a distance of 7 km.
A voltage controlled oscillator (multivibrator) changes the pulse frequency corresponding to an electrical signal obtained from a transducer sensing waves, after amplification. These pulses are applied to a transistorized switch which switches On and Off a transmitter oscillator at 400 MHz. These are received and decoded by sensitive circuits and fed to a pen recorder. Automatic operation for 15 minutes every two hours has been achieved. Facilities of automatic checking of calibration are also incorporated.