Generally speaking, relays can carry far more current that they can switch. If you tune at 500 watts, you should expect to have a hefty repair bill. Using my KX3 into the KPA500/KAT500 I had poor/inconsistent results at 15 watts on poor antennas. My solution was to remove the KPA inhibit and set it to 20 or 25 watts. I seem to remember something a while back to use a minimum of 20 watts for the KAT500. Sorry - I included all my notes and upgrade notes when I sold my KAT500/KPA500.
73 George AI4VZ On Sat, Jul 19, 2025, 12:36 PM dave ingebright via Elecraft < [email protected]> wrote: > Jim, Thanks for your query. I'm tuning at less than 10W, KPA amp always in > STBY. Sometimes the tuner finds a better match at a little more power > (25-75 Watts); someone else mentioned that, too. > But again, yesterday, it found the solution (Multiband ladder-fed G5RV at > 40') 14Mhz, and everything was fine during the first part of the FT8 QSO, > and then the tuner went to a high SWR fault for no apparent reason. > I reset it, and it was fine for the rest of the operating session. It > doesn't matter what band or what power. Remember, I have two of these doing > the same thing. > I still bet there are a couple of little reed relays with pitted contacts > in the auto tuner. I am sure a lot of us have wondered how they get away > with using those in a ~500W high-voltage environment. I will call the tech > line, but wondered if any of you on this reflector have had this problem > //dave > WB7ELY > ______________________________________________________________ > 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] > ______________________________________________________________ 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]
