The first step, if you haven't done it already, is to connect the KPA500 to a good dummy load and test it on 80 meters. That eliminates a problem in the 80 meter bandpass filter in the KPA500.
You can run the KPA300 without the AUX cable (See Fig 3 in the KPA500 Owner's Manual) to test your theory about that being where the RF is getting in. 73, Ron AC7AC -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Robert Redmon Sent: Thursday, October 24, 2013 4:32 PM To: [email protected] Subject: [Elecraft] Fwd: Re: KPA 500 rfi problem and other curious behavior In addition to the display problem on 30 meters described in a previous post, I have never been able to use the KPA 500 on 80 meters. If I run the K3 at 100 watts, the swr shows very low (below 1.3:1) and is consistent. If I put the KPA500 in line, it faults with "high swr" as low as 75 watts displayed on the KPA's display. Also,the swr changes as I transmit, randomly spiking up to full scale and shutting the amp down. It does this with even more frequency at higher power. I have eliminated as many other variables as possible and have come to the conclusion that on 80 meters (only....apparently) enough rf makes its way into the KPA500 to cause this behavior (even at very low power). The antenna is a shunt fed tower, fed with buried hard line about 100 feet from the shack. I feed the same tower (same feedline) on 160 without issue. My instincts tell me the ingress point is the AUX cable (the one thing I haven't tested), but I am otherwise at wit's end. Anyone have any suggestions? Bob ______________________________________________________________ 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 ______________________________________________________________ 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
