AURAL_SWR_INDICATOR

Published:2009/7/3 3:25:00 Author:May | From:SeekIC

Permits blind amateur radio operator to check standing waves on transmission line and adjust for best possible impedance match between source and load.Darkened areas are foil strips 6 x 70mm, 1.5 mm apart, forming inductive trough that transfers RF energy from transmission line to simple aural monitor. Rectified RF energy changes bias on base of Q1, which makes tone increase in pitch with increasing voltage. ldling tone is about 500 Hz for values shown. Operates from three penlight batteries. Transmitter is peaked for maximum output on rising pitch, and matcbox antenna tuner is adjusted for minimum SWR on descending pitch. To lower audio tone, increase size of 82K resistor.-C. G. Bird, Aural SWR Indicator for the Visually Handicapped, Ham Radio, May 1976, p 53-53.



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