Nels, The K3 and your other rigs may be happy with it at 100 W, but at 500 W it may be more critical. The present SWR level (actually, the reflected power) could be just barely faulting the amp. Did you try reducing the drive a bit?
Also: Is there any reason why the LDG tuner can't find a little better match? I've forwarded this to our amp design team to see if they can give you any additional advice. 73, Wayne N6KR On May 15, 2011, at 8:00 AM, Nels Anderson wrote: > Been enjoying KPA500 #32 for a couple of days now. Haven't yet made a > lot of QSOs with it, but the extra power on RTTY and to bust a couple > SSB pile-ups has been welcome. > > However, the amp does not like my 40m setup. As soon as I transmit it > instantly goes into high reflected power fault and shuts down. My > antenna is a 120 foot center fed wire using 1 inch ladder line and an > LDG 1 kw auto tuner. SWR on 40m is under 2:1 and the K3 and other rigs > I've used it with have always been happy with the antenna arrangement. > > In experimenting I used the K3 tune function and reduced the power in > steps to see if I could reach a low enough power level that it would > operate, but even at 1 watt of drive the amp still instantly went into > fault. > > On 80m it did the same thing the first time I tried it, but then I > manually tweaked the antenna tuner, got a lower SWR reading and then > the > amp worked. On the higher bands that I've tried there has been no > problem. > > So, any idea what is causing this? > > 73 Nels K1UR > > ______________________________________________________________ > 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
