Great description. And when dozens of these free running sources are
present (those in our own home and those in our neighbors' homes), the
result can combine to look like broadband noise. This piece, which ran
in NCJ several years ago, provides methods for finding and killing these
sources. The process does NOT start with direction-finding -- that comes
later after we've cleaned up our own homes.
73, Jim K9YC
On 8/11/2021 12:21 PM, Hare, Ed, W1RFI wrote:
Switching regulators make noise ever N kHz, with N being the free running
frequency of the internal circuitry. The noise can be almost a carrier to just
broadband buzz every N kHz, with a 120- or maybe 60-Hz component.
They are also drifty with temperature, change frequency with load changes and
when there is a voltage dip or surge, they do a little burble or change in
frequency to match.
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