[Elecraft] KPA 500

[Don Wilhelm]

Alan,

That does sound like an antenna problem - balun heating, a loose or bad 
connection somewhere.

Try that same test into a dummy load - if it shows the same behavior, 
then you can blame the KPA500, but if not blame the antenna system.

73,
Don W3FPR

On 4/10/2020 7:26 AM, Alan - G4GNX wrote:
> 
> 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.
>