"Ed_G" wrote in
. 192.196:

of the two shields, I fail to see how you can have any current flowing
on the outer shield since the two opposite currents should cancel....
????

I already said that as I understand your variable configuration, it is most
unlikely that there is zero common mode current, or close to it.
Irrespective of the magnitude of the common mode current, the mechanism is
that the coax doesn't 'shield' it.

Owen