What does it do into a known good dummy load? If the same, your amp needs to visit the shop.
If it works with the dummy, it's likely RFI. Adding a common mode choke at the antenna feed along with improved bonding (grounding) would be the first steps towards resolution of your problem. Rick wa6nhc Tiny iPhone 5 keypad, typos are inevitable > On Oct 24, 2013, at 4:32 PM, Robert Redmon <[email protected]> wrote: > > 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
