Using the center conductors of two pieces of coax, with shields
bonded together, does create a balanced transmission line. . .

There's a semantic problem here. I and many others consider "balanced"
to mean non-radiating, which requires that the two conductors carry
equal and opposite currents. Others call any physically symmetrical
line "balanced". As I explained in another recent posting (and in the
article at http://eznec.com/Amateur/Articles/Baluns.pdf), making a
line symmetrical doesn't make it balanced -- that is, it doesn't
guarantee equal and opposite conductor currents and therefore doesn't
guarantee that it won't radiate. A coax line can be balanced and a
symmetrical twinlead line can be unbalanced.

Roy Lewallen, W7EL



In the past, I normally have always used a balanced tuner on my
balanced antenna systems..... this one under discussion, being one of
those SGC antenna couplers, is NOT balanced..... It did not occur to me
that the currents through the twin coax feedlines to the balanced
antenna would not be equal. So, to make sure I am understanding you
correctly, this un-symmetrical current could also occur in open ladder-
line?

Obviously the weakness of my antenna knowledge has been exposed. My
thanks to Roy, AND to Owen.


Ed