[Elecraft] Intermittent low output KPA500

[John Canfield]

Did you try a dummy load? That's always my go-to sanity check when I 
have any kind of an RF concern.

John W5TWO (KPA1500, KPA/KAT500, etc.)

On 4/18/2025 11:00 AM, elecraft-request at mailman.qth.net wrote:
> Message: 1
> Date: Wed, 16 Apr 2025 14:01:11 -0400
> From:phil-z at comcast.net
> To:Elecraft at mailman.qth.net
> Subject: [Elecraft] Intermittent low output KPA500
> Message-ID:<8765654B-73FD-4298-AB39-500CF3445934 at comcast.net>
> Content-Type: text/plain;       charset=utf-8
>
> 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
>
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