[Elecraft] KPA1500 RFI on 10 Meters

[Bob McGraw K4TAX]

I suggest one check the 240V wiring to confirm all connections are tight and solid all the way from the main breaker panel to the outlet for the amp.   This includes L1, L2, Neut, and Ground.   Also I would make sure there is a solid ground between the PS cabinet and amp cabinet.  

Also , since recent issues are reported as new for 10M, make sure the station ground ( if one is used) is not near 1/4 wavelength on 10M.  That’s about 8’ or so. 

73
Bob, K4TAX


Sent from my iPhone

> On Dec 16, 2019, at 4:28 PM, Chris Codella, W2PA <w2pa at arrl.net> wrote:
> 
> 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
>> 
> 
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