Chas, Since you have the KAT2 installed, it may be simply a matter of calibrating the internal wattmeter in the KAT2. If you are using TUNE, be aware that TUNE may produce a power output that is different from the requested power by up to 0.5 watts (up to 5 watts with the KPA100).
While you can use an external wattmeter for calibration, I really don't trust any of them (check their specs - usually 20% of full scale is the speced accuracy, and that is 2 watts on a 10 watt scale). I use a 'scope across a good 50 ohm pure resistance and the formula Vp-p^2/400 when calibrating the forward power (an RF probe could be used instead). I also have a 25 ohm and 100 ohm non-reactive dummy load that I use when setting the SWR at the 2:1 point. In general, I have found that the REFL pot on the KAT2 must be set more clockwise than the FWD pot to obtain the proper 2:1 SWR calibration. Additional note - if the SWR with the 25 ohm load is different than the 100 ohm load, the balance trimmer cap is not set properly - if you have similar loads, you can nudge the trimer a bit until the SWR reported is the came with both loads. Additional note - the KPA100 and the KAT100 reflected power pot WILL be set nearly the same as the position on the FWD pot - but the KAT2 settings will differ quite a bit. 73, Don W3FPR > -----Original Message----- > > I have a question concerning antenna power and SWR. I am setting my K2 > power at 5 watts via CAT. The K2 display reads 4.3 F, 0.0r. An external > watt/SWR dual meter reads 5.9 +/- 0.2 Fwd and a small value > which can't be > read accurately, Rev. A Tandem SWR/Power meter reads 7.2 +/- 0.2 watts > and a SWR of 1.2 +/- 0.1. > > ... > > Also, if the power level is set by the K2 CAT at 5.0 watts, why is the K2 > display reading 4.3 watts? If I have a very accurate wattmeter, can I > calibrate the K2 wattmeter? How about calibrating the CAT setting? I > probably can get a more accurate reading on the Tandem by using a DVM set > on current in series with its meter(s). > > 73, Chas, W1CG > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.322 / Virus Database: 266.11.16 - Release Date: 5/24/2005 > -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.322 / Virus Database: 266.11.16 - Release Date: 5/24/2005 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
