Treadmill combination filter update.
Today I replaced the 10 amp commercial filter with the 20 amp version of
the filter, and the results are similar. Below are a few measurements on
160 meters and 80 meters showing how effective the combination of the two
filters are (14 turn toroid choke, and commercial filter model 20DRGG5 made
by Delta) in reducing my treadmill RFI.
*1.8068 Mhz*
No Filters : 19db over S9
With Filters : S7 which is my noise floor
*1.8291 Mhz*
No Filters : 15db over S9
With Filters : S7 which is my noise floor
*3.5250 Mhz*
No Filters : 28db over S9
With Filters : S6 which is my noise floor
*3.5475 Mhz*
No Filters : 25db over S9
With Filters : S6 which is my noise floor
The 3.5250 Mhz readings indicate the filter is knocking the signal down at
least 46db (and probably more).
73,
Don (wd8dsb)
On Thu, Jan 8, 2015 at 8:14 AM, Don Kirk <wd8dsb@gmail.com> wrote:
> For many years my wife's treadmill caused strong interference on 160 meters
> when it was in use, and yesterday I was able to completely eliminate the
> RFI using a combination of two different filters (a commercial line filter
> that provides both common mode and differential mode filtering, and 14
> turns of the power cord on a 2.4" OD Fair-Rite #31 mix toroid core based on
> the K9YC hams guide to RFI document).
>
> I created a simple website that documents my tests and the filters used,
> and for those interested the website URL is
> http://sites.google.com/site/treadmillrfi/
>
> The website contains a link to a video on youtube where you can actually
> see the effectiveness of the filters.
>
> 73,
> Don (wd8dsb)
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