wrote in message
That is certainly a good theroretical design goal but reality is the
power company and the telco/cableco share the same poles and
underground ducts so their wires do run parallel for hundreds of
miles.
If you are getting ingress on coax or twisted pair, you have another
problem. I bet you could see it using TDR in a second.

On poles, they are often a few feet a part. What is the range or field that
is going to matter? I would imagine the difference between a couple of feet
and touching makes a difference in signal, magnetic field or whatever.