SWR_METER

Published:2009/6/28 23:03:00 Author:May | From:SeekIC

Gives direct measurement of standingwave ratio on transmission line, independent of absolute power levels and of frequency. Voltages of 1N4002 silicon diodes are proportional to logarithms of their cuffents, which in tum are proportional to forward and reflected voltages. Meter scale is nonlinear, with maximum sensitivity as SWR approaches 1:1. For 50-ohm Iine, use 220 for R2 and 27 for R3 and R4. For 75-ohm line, corresponding values are 180 and 33. Detector diodes are pointcontact germanium rated at 80 PIV. Articlegives construction details and calibration curve. Ferrite ring is Mullard FX1596 or equivalent, with 0.5-inch outside diameter. Ground coax braid at one end only.-P. G. Martin, Some Directional Wattmeters and a Novel SWR Meter, 73 Mag-azine, Aug. 1974, p 17, 19-21, 23-24, and 26.



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