Thanks for your input Don. The contest just finished a few hours ago. The PKA100 got a good workout. I'll go inside and tighten the mounting screws on the power transistors (as they recommend) tomorrow.
The SGC autotuner is installed at the feedpoint of a 20m vertical in the back yard, about 80 ft from the house, not in the shack. The K2 and my power meter indicate a perfect match (as one would hope) on 20m, and 1.2:1 on 15m. That of course doesn't necessarily mean there's no RF in the shack, just laying out the setup a bit. I'll run some tests with my dummy load in place and report back. 73 and thanks again, Ken --- On Sun, 2/14/10, Don Wilhelm <w3...@embarqmail.com> wrote: > From: Don Wilhelm <w3...@embarqmail.com> > Subject: Re: [Elecraft] KPA100 - Problems on 15m > To: "Ken Alexander" <k.alexan...@rogers.com> > Cc: elecraft@mailman.qth.net > Date: Sunday, February 14, 2010, 3:08 AM > Ken, > > That does not make sense. The Power output for RTTY > is no different than CW (or TUNE) except that the audio > input to the K2 is different from CW. There is no band > to band difference for the K2 - AFSK modulation is AFSK > modulation no matter which band it is on. > > I would be looking for RF Feedback problems on 15 > meters. Try it into a dummy load and see if things are > normal - if so, look at your antenna system or the > solution. > > OTOH, if all bands behave the same way when operated into a > dummy load, then look to your RTTY driving software and > whatever interface you are using. > > Actually, RTTY AFSK is more related to SSB transmission > than CW, so try SSB as well. If SSB transmission os > OK, then your RTTY driving system is suspect (but would be > the same on all bands). If your problems are confined > to only 15 meters, then look at the possibility of RF > Feedback on 15 meters. > > 73, > Don W3FPR > > Ken Alexander wrote: > > I completed building my KPA100 a few weeks ago. > It passed all tests and checks all the way through. > However, today I noticed something strange. > > > > I'm operating in the CQ WPX RTTY contest this weekend > and spent most of the day on 20m with the Power set to > 50W. I went to 15m to try it out. With the Power > control still set to 50W I hit the Tune button to get my > remote autotuner to tune to 15m. The K2 and my > external power meter indicated the normal 20W, as it should > in Tune mode when the power is set higher than 20W. > > > > When I went to transmit RTTY (without touching the > Power control), my external power meter barely indicated 10 > watts. This only happens on 15m. > > > > As an experiment, I went to the CW portion of the > band. Tune gives you 20W. Keying the transmitter > with my paddles give me 50W. > > > > Any ideas would be appreciated. > > > > 73, > > > > Ken Alexander > > VE3HLS > > > > > > > ______________________________________________________________ > > 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 > > > ------------------------------------------------------------------------ > > > > > > No virus found in this incoming message. > > Checked by AVG - www.avg.com Version: 9.0.733 / Virus > Database: 271.1.1/2685 - Release Date: 02/13/10 03:43:00 > > > > ______________________________________________________________ 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
