[RFI] Putting Toroids on the Service Lines

[Jim Brown]

On 1/28/2013 2:12 PM, Aaron Kreider wrote:
> How crazy of an idea is it to put toroids on the incoming service AC 
> lines? 

Having done considerable research on the use of ferrite chokes to 
suppress RFI noise, it's one of the LAST things I would bother to do, 
except under very unusual circumstances. When I lived in Chicago, the AC 
line was an twisted triplet (120-0-120) with bare neutral, about 80 ft 
long,  that ran about 20 ft below my wire dipoles, and more or less in 
parallel.  I put about six 2-inch long, 1-inch i.d. #31 clamp-ons on 
that feeder, hoping that it might minimize the common mode trash coming 
radiating from that section of the power system.It have helped by a dB 
or two on some bands, but I was never convinced that it did anything 
useful.

73, Jim K9YC