Re: KPA 500

Posted by Vic Rosenthal on Apr 10, 2020; 2:15pm
URL: http://elecraft.85.s1.nabble.com/KPA-500-tp7659606p7659609.html

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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