[RFI] Mystery noise

[Hare, Ed, W1RFI]

Every switcher that has caused me interference has been in my own home, but don't let on. If it ever got out that W1RFI had RFI, my reputation would be ruined. 🙂

________________________________
From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> on behalf of Jim Brown <jim at audiosystemsgroup.com>
Sent: Wednesday, August 11, 2021 4:42 PM
To: rfi at contesting.com <rfi at contesting.com>
Subject: Re: [RFI] Mystery noise

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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