Thanks everyone for the info on the low voltage lights. I'm going to
buy a new transformer and hope that fixes the problem.
This leaves one more source of noise that I have not identified. I have
confirmed that this second noise source is not coming from my home. I
can get a relatively good bearing on it with my HF yagi and my rig tuned
to 20 meters. I hear it on other bands. The amplitude drops as frequency
increases.
I have recorded this noise as a .wav file for anyone that would like to hear
it and/or analyze it, but be forewarned...the .wav file is 1.25M long. I
can probably decimate it if necessary.
This noise sounds like typical power line "buzz". For those DSP buffs out
there, here's the interesting part. I loaded the .wav file into MATLAB
and ran an FFT on it. What I see is 60/30 Hz noise spikes that follow
a sync function pattern with the peak at 1KHz. The 60 Hz noise spikes are
at least 10db greater than the 30Hz noise spikes, but I can see the
30Hz "sync function" just above the noise. In other words, it looks like
a 1KHz square wave modulating a 60 Hz sine wave. Would this be a typical
power line noise signature? If not, any other theories? So, anyone know of
common noise sources employing a 1KHz square wave that may be (intentionally or
unintentionally) modulating a 60Hz sine wave?
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