© 1997 , American Radio Relay

T-network tuners are popular for matching antennas for 160 through 10 meters. Recent articles by Frank Witt, AI1H[1] and Andrew Griffith, W4ULD,[2] addressed how to measure tuner loss for various resistive loads; gave some example calculations and measurements; and showed how to adjust the tuner for minimum loss. Measuring your tuner’s loss is the only sure way to know, but by examining the worst case losses at various standing wave ratios, some useful simplifications and estimates of tuner losses can be made. Simple computer programs can accurately analyze your tuner once you know the component values and all the numerical results here can be obtained in this way, but often a “back of the envelope” calculation can give additional insight. You can, for example, look at a hamfest tuner, or read the advertised specifications of a tuner, and easily make an educated guess of the sort of power loss that you can expect on 80 and 160 meters.