> At 100w on 20m, my KAT500 Utility shows an SWR of 1.00 with the KPA500 on
> Standby and temp around 38ºC. But as I switch the KPA to Operate and
> increase the power to 300w the SWR goes up as high as 1.10. If I hold it
> there (key down) long enough the KPA temp starts rising slowly. At about
> 50ºC I can hear the fan picking up speed. By the time I get to 60ºC the fan
> is at probably level 2 or 3. SWR is still at 1.10 (max).
> Right or wrong, I've always assumed there is some slight heating in the
> antenna system (Tuner, Balun, Lightning protection) although all components
> after the tuner are rated at 5 KW.
> 73
> Lyn, WØLEN
>
> -----Original Message-----
> From:
[hidden email]
> [mailto:
[hidden email]] On Behalf Of Alan - G4GNX
> Sent: Friday, April 10, 2020 6:27 AM
> To: Elecraft Reflector
> Subject: [Elecraft] KPA 500
>
>
> I have a strange fault a couple of times recently, where the SWR starts
> to increase during the time of a single 'over'. I've been using the K3S
> set at 100W out, via the KPA500 (in standby) and the KAT500 tuner,
> without any problem, but after I've switched the linear to Operate and
> driving it to 200W, the SWR creeps up. I don't think it's an antenna
> issue, but a possible heat problem with the KPA500. I watched the
> temperature display on the KPA500 and initially on Standby it shows
> about 38 degrees C. After transmitting at 200W the temperature slowly
> rises above 60 degrees C, but the fan doesn't cut in. Does anyone know
> if this is normal behavior and what temperatures I should expect to see?
> I have tested the fan via the Menu function and it works as expected.
>
> 73,
>
> Alan. G4GNX
>