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Re: Topband: Elimination of Treadmill RFI on 160 meters

To: topband <topband@contesting.com>
Subject: Re: Topband: Elimination of Treadmill RFI on 160 meters
From: Don Kirk <wd8dsb@gmail.com>
Date: Mon, 9 Feb 2015 07:07:46 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
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 having success using filters on their
treadmill similar to what I used which have provided excellent results.

73,
Don (wd8dsb)
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