Ian, the efficiency of the KPA100 in the K3 varies quite a bit from band to band, hence the current draw needed to attain 100 watts varies. That's normal.
I'd not be concerned about your numbers. To illustrate, I took a minute to check the current required by my K3 on all the bands feeding a dummy load: 160M - 17.45A 80M - 15.1A 40M - 14.9A 30M - 17.3A 20M - 18.2A 17M - 15.8A 15M - 15.4A 12M - 20.3A 10M - 12.1A 6M - 14.6A The current demand from K3 to K3 will also vary, so don't be surprised by some variations. Also, the voltage on mine stayed between 12.9 and 13.2 volts under load. The lower the supply voltage, the more current required to produce 100 watts. 73 Ron AC7AC -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Ian Kahn - Ham Sent: Thursday, January 10, 2013 7:23 PM To: mcduf...@garymcduffie.com Cc: elecraft Subject: Re: [Elecraft] New Output Power Issue So, several weeks after originally starting this thread, I finally had time this evening to sit down and take some voltage and current measurements. I used my Astron SS-30 power supply connected to the 40A DC-in port on my Rigrunner. I then ran the Elecraft power cord from a 25A port on the Rigrunner into the 12V DC-in on the back of the K3. Everything measures 13.8V in standy/rx, all the way to the reading on the K3 display, with the K3 showing .82A current draw in rxv. I would measure the power at the 12V in port on the K3, but can't see a way to get the probes into the powerpole connectors without damaging anything. I ran my tests using FSK-D at 100W and into a known-good 300W dummy load, so I could get 100% duty cycle for a few seconds with each transmit. When I go to transmit, voltage on every band looks good, with the voltage dropping from 13.8V to anywhere from 12.1 to 12.4 volts. I'm concerned about some of the current readings, however. 80 meters shows a current draw of 15.80A; 17 meters shows a draw of 16.35A; 15 meters shows a draw of 16.40A; 10 meters shows a draw of 12.93A. 12m, 20m, 30m, 40m, and 160m are all within the 17-22A current draw rating for the K3. The RF output meter on the K3 shows 100w out on every band, but I haven't put the rig on an external watt meter. Since these are all below the nominal current draw given in the K3 owner's manual (17-22A), is there something I should look at recalibrating? Or could something more serious be going here that I need to be concerned about? Or, am I worried about nothing? Further guidance is greatly appreciated. Thank you and 73, --Ian ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
