Leaderboard

Greg, I fully agree with this, and I'll admit that I was trying to simplify something that just isn't so simple. If the antenna has a high SWR, a wattmeter may not read correctly anyway, due to the reflected voltage not necessarily being at a half-wave point in the return path. The main problem is that many consumer-grade RF power meters do not actually measure power. They measure a sample voltage at a given point in the transmission line, and estimate power based on a low-voltage/high-current place on the line. Reflected power, depending on the phase and time of arrival at the metering point will either add to, or subtract from, that representative voltage, giving a false reading. For example, if your input jumper is too long, and falls at a voltage high point in the overall line length, and the reflected power from a mismatched antenna also falls at a voltage high at that same point in the line, your voltage-driven power meter may show 45 Watts output from a 25 Watt transmitter. With a half-wave input jumper, you will start out with a known voltage low point. A mismatched load will still cause a false reading, but usually not as severe. - Your reading will be "less wrong". I guess in summary, if you want to measure output power of your transmitter, use a known good terminating resistor - A.K.A. Dummy Load. I've seen good 50 Ohm terminators selling for less than $40.