TIMER_IS_AUTOPATCH_KEYER

Published:2009/7/20 2:03:00 Author:Jessie | From:SeekIC

Simple keyer oscillator using NE555 timer was designed for autopatch in repeater having decoder bandpass from 2980 to 3080 Hz. Adjust R2 to 3042 Hz. 0ut-put options for loudspeaker and microphone are shown. Adjust R3 for required input/output level; use variable resistor if desired. Normally closed keyer contacts can also be connected between pin 7 and ground. Supply can be 9-V transistor radio battery.-E. Noll, Circuits and Techniques, Ham Radio, April 1976, p 40-43.



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