Hi Jim,
Your 1/2 mile RF flooding RFI experience is similar to mine. I've only
been able to resolve a few RF flooding RFI cases from nearby homes.
In each case the problem was a wall wart, especially Apple iPhone
and iPad wall warts.
One of the worst unresolvable problems is smoke detectors permanently
connected to AC power wiring. I can correct them in my own home,
but for obvious reasons not in neighboring homes.
73
Frank
W3LPL
----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: rfi@contesting.com
Sent: Friday, September 15, 2017 6:05:32 PM
Subject: Re: [RFI] SO2R and 2nd harmonic
Frank,
I don't view this as an "either-or" situation. That is, BOTH our own
transmitters and these external non-linear distortion generators can be
causing the problem. When both are present, BOTH proper stub design/good
coax wiring AND finding/defeating the external non-linear distortion
generator are required.
It's the same old story of "peeling the onion" with multi-element
problems. You fix one element, allowing you to hear the other underlying
components that were obscured by the one you fixed.
Using the contesting trailer documented in k9yc.com/7QP.pdf, we had no
issues with harmonics when set up in the middle of nowhere, but DID have
issues with external distortion sources when set up within a half mile
or so of "civilization."
73, Jim K9YC
On 9/14/2017 10:13 AM, donovanf@starpower.net wrote:
> Dave's reply is the only one that correctly addresses the problem
> you described. You described your problem as " rise up floor noise
> level about 60 khz on each side from main harmonic frequency."
>
>
> Many contest stations -- including mine -- experience the exact
> problem you describe, it has a name: "RF Flooding" Its caused
> when a powerful RF signal penetrates a non-linear device that has:
> - AC power or digital signals flowing though it, and
> - is connected to wires that receive the powerful fundamental RF
> signal and re-radiate broadband modulated harmonic RFI.
>
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