Nowhere has there been a mention of what VSWR the tuner sees, only the result of its match which is 2.5:1. That means the VSWR it sees is beyond its capability to tune properly and run full power. This information is available on the KPA1500 panel display. It will also state the maximum allowable power output. What are those values?
I suspect the VSWR is quite high and the allowable power well below 1,500 Watts. It's likely you're expecting more power-handling capability than the BALUN, either one, can handle. When one writes "quickly" that is interpreted differently by all those who read it. Obviously, 20 to 30 seconds is not "quickly", at least to me, but a very good indications of something overheating, but not instantly. The latter could lead toward a very different conclusion. My current (pun intended) conclusion is don't run over 800 Watts on 160m! That is about the same level you run with your other amplifier without a failure, maybe, if you don't run it too long at that level. I'm glad you concluded it's an antenna system problem. BTW, W8JI has written about this antenna and recommends an 80-20% ratio, rather than the typical 67-33% ratio. He has modeled it for various bands on his web site. I don't know why the common 67-33% values are used when someone has shown there is a better choice. Old habits, good and bad, die hard. 73, Bill, K8TE -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ 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 Message delivered to [email protected]
