[Elecraft] KAT 500 SWR FAULTS [INTERMITTENT]

[George Danner]

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 <
elecraft at mailman.qth.net> 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
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