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

Aaron Kreider aaron at campusactivism.org
Fri Dec 6 19:25:59 EST 2013


Thanks for you advice.

On 12/5/2013 12:45 AM, Jim Brown wrote:
> 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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