Sounds similar to what my barefoot K2/100 was doing with an LDG tuner to a multiband ladderline-fed doublet. It would tune up alright but as soon as I started talking on 17m the tuner would go crazy. I replaced the first few feet of feedline with dual coax, grounded the shields. That moved the open twinlead a few more feet away from the rig, and it presented a slightly different impedance to the tuner. No more problems.
I don't know what configuration you have between the tuner/balun/feedline but you might start there. 73, Dennis NJ6G On 5/15/2011 11:41 AM, [email protected] wrote: > Sounds to like your LDG Tuner can't match the load... > > 73, > Tom > Amateur Radio Operator N5GE > > > On Sun, 15 May 2011 11:00:57 -0400, Nels Anderson<[email protected]> 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
