[RFI] U-VERSE & 75 meters

[Jim Brown]

On 11/17/2010 2:22 PM, Kelly Johnson wrote:
> How can
> common-mode filtering fix it?  Isn't this a case that requires the
> bucket treatment?

Not necessarily.  The SIGNAL is differential, but the primary coupling 
mechanism of RFI is common mode, so SERIOUS common mode suppression can 
make a big dent in that part of the problem.

Now, the differential path must also be VERY resistant to coupling at 
the frequencies of interest.  A good starting point would be the best 
quality CAT5 cable for the part of the path that is in the near field of 
the interfering signal, combined with excellent shielding of all 
electronics in the near field, and common mode filtering of all cables 
that enter/leave the electronics.

73, Jim K9YC