VHF field strength meter

Posted on Feb 5, 2014

This is a simple and low cost wide band VHF field strength meter. The field strength is measured by converting the radio signal to DC and measuring it. The RF signal will be picked up by the coil and rectified by the diode D1. Even a very small DC voltage is sufficient to alter the biasing of FET and it will be reflected in the meter as an indicati

VHF field strength meter
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on of the presence of a radio signal. The meter can be calibrated by adjusting the preset R2 to make meter M1 read ZERO in the absence of any radio signal. This circuit is not very sensitive, but can sense radio signals from hand held FM transmitters up to a distance of few meters( ideal for theoretical demonstrations).

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