ANTENNA_ROTATOR_1

Published:2009/6/26 3:59:00 Author:May | From:SeekIC

Developed for use with CDE TR-44 antenna control using low-voltage AC motor having pot for bearing indication. Circuit eliminates need for holding control handle in position until antenna reaches desired bearing. Uses 12-VDC 1000-ohm 1-A relays, TISN7274IL opamp U1, and wirewound 360° rotation command pot R7 operating from 14-V regulated supply of original control. When R7 is set to desired new heading, relay applies power to motor for proper direction, and drops out when antenna reaches desired heading. One relay is used for each direction of rotation.Opamp is connected in differential-input mode that responds only to difference voltage between wipers of pots R7 and R8. Polarity of oparnpoutput dependson polarity of input voltage difference. CR3 and CR4 energize K1 or K2 depending on polarity of error signal. R9 and R3 serve to balance voltage difference remaining when R7 and fi8 are at travel limits. R9 also nulls offset present when there is no input to U1. Ac-curacy is about 5°. Diodes are 100-PIV 0.5-A silicon.-K. H. Sucker, Automating the TR-44 An-tenna Rotor, QST, June 1973, p 28-30.



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