[RFI] RFI Signature

David Eckhardt davearea51a at gmail.com
Sun Nov 23 15:42:52 EST 2025


QUOTE:   1. On the pan adapter, looks like power line noise.  Random dots
                        across the screen.

Powerline noise would appear on an o'scope as a double exponential every
120 Hz or 8.3 ms.

Dave - WØLEV

On Sun, Nov 23, 2025 at 7:20 PM Jeff (W4DD) <w4dd09 at gmail.com> wrote:

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> I am working on a RFI case that we believe is coming from a nearby home.
> The owner is a little cooperative, but is not interested in doing a ckt
> breaker test.  The noise exhibits some interesting characteristics that may
> help us in suggesting he unplug a device.  Perhaps someone has seen this
> before.
>
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>
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> 1.      On the pan adapter, looks like power line noise.  Random dots
> across
> the screen.
> 2.      No repeating clusters of noise vs frequency that might suggest a
> SMPS.
> 3.      No correlation to sunlight or darkness.  No correlation to time of
> day.
> 4.      Has distinct levels of interference; we have noted -85dBm, -78dBm,
> -72dBm (S-9), -66dBm.  Interesting the levels are about 6dB apart.  -78 and
> -72 are most common.
> 5.      The neighbor has a solar system installed roughly 2 years ago, but
> as mentioned, no correlation to sunlight/darkness or time of day.
> 6.      Affects mostly 80M but can be heard on other bands
>
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> Has anyone seen 4 levels of noise from a device before?
>
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> Thanks for any ideas.
>
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> Jeff, W4DD
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>


-- 

*Dave - WØLEV*


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