[Elecraft] Intermittent low output KPA500

phil-z at comcast.net phil-z at comcast.net
Wed Apr 16 14:01:11 EDT 2025


In the last few days I have noticed that when operating FT8 using my KAT500/KPA500 combo with an IC-7610, my output seems low on the first or second transmit cycles after switching bands. If I am chasing DX I usually run about 120 to 160 Watts, which is about 6 to 8 Watts on the transmitter. I am seeing only 50 or 60 Watts on the amp when I first transmit. After a couple cycles it goes to the higher output and is stable after that.

When changing bands, I switch the radio, with the amp in Standby, then switch bands on the amp before transmitting. Sometimes I use Tune in WSJT-X running just a few watts with the amp in Standby for the amp to automatically switch bands. My antennas have low SWR on most bands, so the tuner is often in Bypass. 

This seems to have just started and most often occurs on 20 Meters using a GAP 20 Meter Mono-band. 

I also run CW and some SSB but don’t notice the power meter as much as on FT8. I don’t thing it’s happening there.

Has anyone seen this or a similar problem? 

Phil N3ZP


More information about the Elecraft mailing list