3_50WPM_KEYER

Published:2009/7/11 5:12:00 Author:May | From:SeekIC

Uses NE555V 1 as switchable dot generator providing accurate 1 : 1 ratio.SN7473 U2 forms variable dash circuit. NE555V sidetone generator U4 has tone range of about three octaves and easily drives 3-W 4-ohm loudspeaker through small transistor-radio transformer TR. NE555V US acts with U4 to provide two-tone oscillator for SSB tuning. Output section Q1-Q2 easily handles keying bias of -26V at 5 mA.-H. Seeger, Micro-TO Keyer Mods,Ham Radio,July 1976,p 68-59.



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