[RFI] Does anyone recognize this RFI?

[K9MA]

Ah, but they ARE drifting! I don't think the resolution in this image is 
good enough to see the modulation.  The switching supplies I see usually 
are spread out over just a couple kHz.

73,

Scott K9MA


On 4/15/2020 12:27, Jim Brown wrote:
> On 4/15/2020 9:48 AM, K9MA wrote:
>> Looks like a switching power supply running at 55 kHz.
>
> Unlikely. SMPS are free-running, modulated by noise, so they are 
> "humps" of noise that drift. These signals are stable in frequency 
> with no modulation.
>
> 73, Jim K9YC
>
>
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-- 
Scott  K9MA

k9ma at sdellington.us