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Solved RFI problem...

May 25th 2016, 20:48

nk7z

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Thought I would drop a solved RFI problem here... Maybe wake the place up a bit, it seems too quiet!

My Sears LG refer is about 15 feet from my BWD-90 broadband TFFD antenna. It is like a dipole, only worse, but it is under 2:1 everywhere. See: https://en.wikipedia.org/wiki/T2FD_antenna for more info on it.

When I am on 40, I get all sorts of RFI from the fridge, using this antenna... Not surprising.

What is surprising is that the addition two mix31 large ferrites ended the problem almost! I ended up making two turns of power cord through each one, binocular style. There was just a slight bit of RFI remaining. I added more cores, and no change. I added still more and no change... It is as if I hit a wall... The refer is a full metal case, so I tightened everything on the fridg, still no change, just that same bit of RFI left, and nothing I could do would change it.

The refer is fed water via a copper tube, going to a cold water pipe, which is copper. I noticed as I coiled the copper tube in prep to finish, the remaining RFI changed as I touched the copper tube!

My first thought was what gives here, this is ground! Turns out the main feed for the house is PVC, and the entire home is done up in copper... So it is not a ground, it is an antenna! I added a mix31 ferrite to the copper tube, (yes, I just clamped it on the tube), and the problem ended...

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