[Elecraft] KPA 500

[Victor Rosenthal 4X6GP]

I would be more likely to suspect something after the KPA500, such as 
the tuner or a balun. I've experienced significant balun heating, 
especially when using a balun other than a straight-through 1:1 balun, 
or when the load is highly reactive. Balun power ratings assume a 
non-reactive load.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/
On 10/04/2020 14:26, 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.
> 
> 73,
> 
> Alan. G4GNX
> 
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