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Re: [RFI] Elimination of Treadmill RFI on 160 meters

To: Don Kirk <wd8dsb@gmail.com>
Subject: Re: [RFI] Elimination of Treadmill RFI on 160 meters
From: dalej <dj2001x@comcast.net>
Date: Sun, 8 Feb 2015 17:20:10 -0600
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
FYI, my Lifespan TR4000i which I just had installed a week ago is quiet as a 
church mouse, both RFI-wise and audible-wise.  

Dale, K9VUJ


On 08, Feb 2015, at 16:49, Don Kirk <wd8dsb@gmail.com> wrote:

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)
>> 
> 
> 
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