Thanks again, Don. It's good to know that the variation in current isn't a problem. I was also a bit surprised with the 12M and 20M measurements.
I think I will do a complete realignment of the K2, and set up the wattmeter on the KPA when I get the LP100 back. Meanwhile, I'll try a few QSOs at 50W or so and see what happens. 73, Jim KO5V -----Original Message----- >From: Don Wilhelm <[email protected]> >Sent: Nov 9, 2018 5:15 PM >To: Jim KO5V <[email protected]>, Bob McGraw K4TAX <[email protected]>, >Elecraft List <[email protected]> >Subject: Re: [Elecraft] K2: KPA100 fan issue + current question > >Jim, > >That is normal. The Transmit RF Gain varies from band to band, and that >will cause the current draw to vary. I am surprised that 12M is so low, >it is normally on a par with 10 meters. > >Part of the RF Gain variation is in the base K2 and some more of it is >in the KPA100. > >Remember that those are steady state current draws. The dynamic current >such as with SSB operation may peak at greater than what you measured. > >Yes, use the LP-100 for calibrating the KPA100 wattmeter. Since the >LP-100 has NIST traceable calibration, I would believe it over the >readings on a calibrated BIRD. > >73, >Don W3FPR > >On 11/9/2018 5:56 PM, Jim KO5V wrote: >> Don and Bob, >> >> The K2 and amp are both powered from the amp's supply. >> >> I used a known good DVM to measure the voltage across R7, and it agrees with >> old Beckman. I now think my old kit-built Ten Tec power meter may be badly >> out of calibration. I have a dead LP-100 that is on its way back to Larry >> for upgrade and calibration, so I'll just wait until it is back to finish >> calibrating the KPA's power setting. >> >> Here are what I measured and calculated at the approximate center of each >> band, in cw, when the K2's LCD read 100W: >> >> 10M: .067V, 13.4A >> 12M: .049V, 9.8A >> 15M: .064V, 12.8A >> 17M: .065V, 13A >> 20M: .048V, 9.6A >> 30M: .056V, 11.2A >> 40M: .052V, 10.4A >> 60M: .056V, 11.2A >> 80M: .054V, 10.8A >> >> The current seems to vary significantly between bands, but maybe that's >> normal? >> >> > ______________________________________________________________ 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 Message delivered to [email protected]
