[Elecraft] KPA1500 RFI on 10 Meters

[Chris Codella, W2PA]

Scott,

I noticed the same thing this last weekend, having not been on 10 much 
since getting the amp.  But I found the noise to be quite variable.  It 
doesn't always occur.  When it does, it appears suddenly, out of the 
blue while operating.

Sometimes I could make it go away by turning off the power, waiting a 
while, then restarting.  I also got it to stop a couple of times by 
sending a single "dit" while in operate mode.  Quite strange. I'm trying 
to get more data but it does seem to be an intermittent thing and hard 
to replicate.

This noise didn't affect any band below 10m but appeared very 
broad-banded above, using an SDR receiver.

73,
Chris, W2PA

On 12/14/2019 4:43 PM, K9MA wrote:
> I guess it just shows how little I've been on 10, but I've had the 
> KPA1500 for over a year now, and I just noticed that when I turn it 
> on, my noise floor on 10 goes up about 3 dB. (And that's from an urban 
> noise floor.) It's pretty flat over much of the band, not typical 
> switching supply noise. Has anyone else experienced this and found a 
> cure? (Other than using the old amp tube.)
>
> 73,
>
> Scott K9MA
>