For a moderatly complete study of twisted pair ingress/egress see:

http://www.comsoc.org/sac/private/2002/june/pdf/20jsac05-stolle.pdf#search='twisted%20pair%20ingress'

Get those calulators out.

Please note that this studies much higher levels of "RF" then the
typical SW receiver will be
"see". So what is acceptable for a networking or telco environment, may
not be acceptable
for a receiving use.

A comparison betweent the details int his link and the coax link:
http://www.tennadyne.com/pdf/coaxial_tenn.pdf
could be educational.

Or maybe not, after all some people still insist the world is flat.....

Enjoy!

Terry