[RFI] RFI LG Refrig Corcom filter and #31 core

[Don Kirk]

Hi Jim,

Once again the toroid core choke did not eliminate the RFI on its own.  We
tried the K9YC toroid choke by itself and it did not eliminate the RFI, we
tried the corcom filter by itself and it did not eliminate the RFI.  It was
only when we used both filters in series that Mike reported the RFI was
gone.  I also tried the toroid choke before and then after the corcom
filter with identical results on Mike’s RFI.

This is not the first time that I have had to use both filters to eliminate
RFI.  The first time was on my wife’s treadmill.  It really is an
interesting phenomena.  I suspect we would notice some components of the
RFI disappear if looking at it with my SDR receiver or spectrum analyzer
when using each filter on its own, but the bottom line is that both filters
were required for Mike ti noice the RFI disappear.

Just FYI,

Don wd8dsb

On Wed, Sep 29, 2021 at 3:50 PM Jim Brown <jim at audiosystemsgroup.com> wrote:

> On 9/29/2021 12:10 PM, Mike Wetzel wrote:
> > My neighbor's LG refrigerator is radiating RFI on 28MHz and Don (WD8DSB)
> > temporarily hooked up a Corcom filter and a cord wrapped around a #31
> > torroid core that eliminated the interference.
>
> I'd bet that the turns around the toroid were doing all the work. Noise
> is most often on the green wire, which is a chassis-to=chassis
> connection on the filter.
>
> 73, Jim K9YC
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