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TopBand: RFI: HELP!

To: <topband@contesting.com>
Subject: TopBand: RFI: HELP!
From: W8JITom@aol.com (W8JITom@aol.com)
Date: Fri, 11 Oct 1996 10:25:03 -0400
Hi Scott

In a message dated 96-10-11 08:58:56 EDT, you write:

>At the time I was on the rx ant listening to a JA, I flipped to the
>Inv-L which is further away from the shack and the noise seemed to drop
>some, probably 2 s-units. I had a feeling that I knew what it was, so I
>went up to see if the TV was on, and sure enough, it was. The xyl was
>watching the Today Show.

The same cures for TVI apply to RFI generated by the TV. The problem is much
more likely the TV set has two wires attached to it that allow it to radiate
a good signal, rather than through the case radiation.

Connect the antenna cable shield (assuming you have coaxial cable) to the
power line NEUTRAL lead (assuming you have modern wiring with a safety
ground) near the TV set. If you have multiple things connected, use a
bypassed outlet strip (a three wire grounded type) and connect the cable
shield to the outlet strip. The devices manufactured for lightning
suppression work very well, because some have a connector to feed the antenna
lead through.

You can add clamp on chokes between the outlet strip and the TV, but at that
point NEVER wind the line cord and antenna cable through the same core. You
can also add chokes over the lead from the outlet strip and antenna cable
where they go to the outside world, but these should be common chokes
covering both wires.

Also be sure your 160 antenna feedline is properly decoupled, and that none
of the antenna (including any elevated radials) is near the house. The
feedline can conduct unwanted signals and noise to the antenna, and if you
only use a few radials they can act like antennas and pick up unwanted
signals.

Good luck.
Tom


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