Topband: Zo of an individual CAT5 twisted pair

[Jim Brown]

On 8/14/2013 12:42 AM, Tom W8JI wrote:
> The important point is voltage from each conductor to surroundings is 
> what really determines the gender of balance, because ideally both 
> coax and twinlead have equal and opposite currents in the two conductors.

Ideally = Alice In Wonderland.  I've never met anyone who lived in the 
ideal world who wasn't smoking that funny smelling stuff.

This "ideal" makes the wildly optimistic assumption that the 
terminations on both ends are balanced, which is rarely true. The 
problem is that noise cancellation depends upon very DEEP cancellation, 
which required equal magnitude AND equal phase. That's a lot to ask of a 
real antenna, and of a real circuit, over a limited range of 
frequencies, let alone a wide range.

73, Jim K9YC