[Elecraft] KPA1500 RFI on 10 Meters

[Charles Johnson]

I see no difference whatsoever on 10M with the KPA1500 powered on or off, or with the TH7DX tribander pointed at the station or pointed at some other azimuth. My resting noise level on 10M is approx -125 dBM on the P3. The tower is about 60 feet from the station. 

73, Charles, K4ZRJ

> On Dec 17, 2019, at 14:07, K9MA <k9ma at sdellington.us> wrote:
> 
> 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
> 
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