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

Jim Brown jim at audiosystemsgroup.com
Thu Dec 5 00:45:38 EST 2013

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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