[Elecraft] KPA1500 RFI on 10 Meters

[K9MA]

Chris,

In my case, the noise is present any time the KPA1500 is turn on. Its 
effect depends only on the direction my beam is pointed, as both my 
noise level and the amplifier noise vary with direction. In the worst 
case, I'm seeing about a 5 dB increase from my high urban noise floor. I 
think the effect would be far more dramatic in a quiet location. (My 
antenna is about 100 feet from the amplifier, which is in the basement.)

73,
Scott K9MA

On 12/16/2019 16:16, Chris Codella, W2PA 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
>>
>

-- 
Scott  K9MA

k9ma at sdellington.us