[RFI] Adding a shield to the utility service lines?

Kenneth Goodwin krgoodwin at comcast.net
Thu Dec 5 15:28:10 EST 2013

When I built my house, I decided to go underground from the pole (step-down
transformer) to the house.  I had to purchase the wire and pay the
electrical contractor to bury it in conduit (read as expensive for 200 A
service).  As 'my' line came off the pole, I had the contractor install my
surge device spliced into 'my' line near the top of the pole.  A few years
later, the power company removed it without telling me.  I complained.  In
short, they control everything from the service meter outbound.   No
questions tendered as long as you desire electricity.  I ended up installing
a surge protector system in the circuit breaker system.  Ken K5RG

Message: 2
Date: Wed, 04 Dec 2013 21:45:38 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: rfi at contesting.com
Subject: Re: [RFI] Adding a shield to the utility service lines?

On 12/4/2013 9:33 PM, Aaron Kreider wrote:
> Another crazy option

Yes, it is.  Shielding addresses differential mode RFI, and most trash on
power lines is a common mode signal and radiates just like any other
antenna. Although I tried a bunch of big clamp-ons on a twisted triad power
feed back in Chicago, it was long before I understood how ferrite chokes
work, and I'm now nearly convinced that it was a bad idea because a string
of beads is inductive.

Even if you could shield that line (it belongs to the power company, so it's
not a good idea), the common mode current would flow on that shield, and you
would still need to choke it to prevent it from radiating.

73, Jim K9YC

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