Data from another treadmill RFI success story.
A few days ago Lionel (N5LB) added filters to his treadmill based on what I
had done to eliminate RFI from my wife's treadmill, and below are his very
successful results.
----------------------------
Don
I want to tell you my results with the treadmill and the delta filter.
Before the filter:
160m - 91 dbm
80m -77 dbm
40m -97 dbm
20m -93 dbm
15m -97 dbm
12m -110 dbm
10m nil
After the Delta install
160, 80, 40, 20 m below the mds at - 131 dbm
15, 12m -110 dbm
After adding a FT240-61 with 7 turns of #12 stranded in the line side of
the Delta.
160 - 10m not measurable, mds is ~ -131dbm. Not visible on Flex 5000
waterfall.
All of the dbm readings are from the Flex 5000 meter. S7 = ~ -90 dbm so
the RFI was really bad.
So like you case I needed additional filtering. For me it was higher in
frequency so the Delta attenuation must drop off above 20m. I was able to
fit the Delta and the toroid inside of the treadmill motor and control
housing making for a neat install.
Thanks for the excellent suggestions. I bought the Delta from Digikey and
had it 36 hours later, incredible service.
Lionel
----------------------------------------
Note that Lionel used the same Delta Filter that I used (model : 20DRGG5).
He used an FT240-61 core which he had on hand with 7 turns of the Hot and
Neutral wires passing through the core (ground wire die not pass through
his core) whereas I used 14 turns of the power cord on a 2.4" OD Fair-Rite
#31 mix toroid core (Neutral, Hot, and Ground wires passing through the
core).
Just FYI, and glad to hear others are success using filters on their
treadmill similar to what I used which have provided excellent results.
73,
Don (wd8dsb)
On Mon, Jan 26, 2015 at 8:19 PM, Don Kirk <wd8dsb@gmail.com> wrote:
> 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 8:11 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. 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)
>>
>
>
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|