Following up on an exchange I had some time ago with Larry, I couldn't figure out why his LP100A watt meter was reading low - even after he had calibrated it in his shop. With some help from Don W3FPR, I got it figured out and offer this for future reference to others who may experience the same confusion.
There is a procedure on page 49 on the K3 manual to calibrate the power out on the K3. After doing this you calibrate "per-band" using a procedure on the same page. I didn't realize the K3 power meter is not absolute. In other words, this procedure on page 49 is what tells the K3 power meter how much 100 watts really is (actually 50 watts is used for the test). I had calibrated my K3 watt meter some time ago against an MFJ-949E antenna tuner watt meter. (OK stop laughing). Turns out the MFJ unit and another cheapo SWR meter I had here were both way off. The MFJ reported 100w when the true output was more like 70. As a result, even though my K3 watt meter read 100w, in perfect agreement with the MFJ, both were wrong. I re-calibrated, per Don's suggestion, using the LP100A as the reference. Now 100w on my K3 shows 100w on the LP100A and 125 watts on the MFJ. As an added bonus, my amplifier now puts out full power as it was being under driven before. -- Buck k4ia K3 # 101 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
