[Elecraft] Hot KXPA100 Amplifier

[David Ahrendts]

Would second all of this fine advice. I run the KX3 + PX3 + KAT100 into an Ameritron ALS-600S. And those clamp on chokes are essential. Using them liberally, and also making sure all the control mini-cables come no where close to the high-power coax outputs or the output from the KX3. Tidy things up nicely. Keeps the RF going where it should go.

David A., KC0XT

> On Jan 31, 2015, at 10:59 AM, Jim GM <jim.gmforum at gmail.com> wrote:
> 
> Durring the last month of the ARRL Centennial QSO Party I was behind on
> points to get into the top tire. So I finally turned on the amp and started
> calling CQ on 20 -10 Meters. I noticed the the amp was getting hot and
> finally tripped out on high heat. cooling fan helped but not as well as I
> hoped.
> 
> I also noticed that the amp ATU would start to re tune on my transmit
> frequency more than I would like. I finally tracked down the issue and came
> up with a solution.
> 
> RF was coming back on the RF output cable between the KX3 and KXPA100. Some
> RF was also coming back on the other cables as well.
> 
> I installed some of those DX Engineering clamp on choke cores. I bundled
> the inter-connecting cables and put 3 of those cores around those cables. I
> separated the RF output cable from the bundle, and took one clamp on core
> and wrapped one turn  close to the amp. Took care of my problem and the amp
> ran as cold as a cumber in the frig.
> 
> COMMON MODE CHOKE POWER !!!  :-)
> 
> -- 
> Jim K9TF
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David Ahrendts   davidahrendts at me.com