Hi Tom, Regrading your comments below:
I am seeing a similar concern with my KX3/KXPA100 home station. The KXPA100 ATU tunes it right down to 1.1-1.2. Then when I start transmitting it jumps up between 2 and 3. This doesn't happen all of the time nor on all bands. I have worked with Dick and he has put a lot of effort into my concern, much of it off hours by the way. Great service and great concern demonstrated by Dick. Try to get a response from the big three at all-let alone on weekends. We ran traces on the tuning process and it shows a good tune right down to where it needs to be. However, the SWR then jumps up when I go to full power. I am not sure it is a real problem as the power meter shows I am getting out OK. But it is concerning to be transmitting 100 watts and seeing the SWR jump up to 3 after it has tuned down to 1.2. I don't believe it is in my antenna because I put an LDG tuner in the line and it tunes solid and stays there. I know gut feel isn't very scientific but I think there could be an issue with the SWR circuitry. At lower tuning powers it senses SWR OK, but with higher power levels it doesn't. It may well be that my SWR is varying and maybe the sensing circuits in the KXPA100 are just more sensitive than the LDG circuits, I don't know. All we really know at this point is that the traces look really good, the ATU takes the reported SWR down to more than acceptable values even when the antenna SWR is above 10. I may try putting a variable dummy load on it to see if I can duplicate the problem into a known stable load. Keep in mind that this is more of a nuisance item to me and I love the KX3/KXPA100 combination. 10m was wide open this weekend and I worked Japan, New Zealand, Hawaii, and China with a very minimal horizontal loop at 15 feet. I know this is anecdotal but I believe the low noise receiver and filtering made it possible. Good stuff! Tom/AE5QB
From responses to my original post, several people have mentioned SWR instability they believe associated with the KX3 rather than connections, feeder, antenna, etc. Of course, that being said it is completely possible the problem might indeed be an antenna (in my case often used in windy conditions when mountain-topping), feeder, etc., heating issue in antenna or component or poor connection, most likely in feeder. So far this week I've not had the opportunity to investigate further but I plan to. Please keep me posted on anything you discover in further conversations with Elecraft. Thanks to everyone else for your input on the topic and I'll let you know what I find as soon as I have the chance to try a few equipment combinations. Interestingly enough in my case this problem has only started to occur recently. So something has changed, whether associated with antenna, feeder or radio. I did not see this issue on my first 14 or so SOTA activations.
Best regards, Gary K6YOA ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
