On 12/19/2022 1:04 PM, k1ttt.dave@gmail.com wrote:
Signals like that which move up and down are generally something like
harmonics of switching power supply or variable speed motor or some other
non locked frequency digital system, that is, something that doesn't rely on
a specific clock frequency like computers, tv's, modems, ethernet, etc
require.
Every one of them that I've seen is frequency-modulated by noise, so in
addition to drifting, it's a band of noise. And this is at 2M.
Power supplies drift with temperature, line voltage, or load. The
step functions you see may be because the sdr only processes the spectrum a
few times a second so they appear to stay the same for a short time then
jump a bit as the next set of samples is plotted and the signal has moved
into the next fft column range.
Maybe, but I'd like to know what this noise sounds like.
73, Jim K9YC
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