AUDIBLE_S_METER

Published:2009/6/30 22:12:00 Author:May | From:SeekIC

When connected to repeater circuit generates tone burst 3 s after input signal has dropped out, with duration of 60 ms. Pitch of tone varies inversely with signal strength; highest pitch of 3500 Hz thus represents weak signal, and 350-Hz pitch corresponds to strongest input signal. Can be used to check performance of transmitters and antennas using that repeater. Repeater receiver must havesmeter, as in RCA CA3089E receiver, output of which can be fed to terminal A of circuit. Switch changes output from S-meter to audible encoder. Input B goes to squelch, C goes to +12 V source that is on when receiver is on, and D provides tone output for feed to audio amplifier and loudspeaker. Unlabeled transistors can be any medium-gain small-signal NPN and PNP silicon, comparable to European BC107 and BC177.-F. Johnson, Audible S-Meter for Repeaters, Ham Radio, March 1977, p 49-51.



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