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.


No, I wouldn't say "shield" would be a proper term, either. But I
would suggest that a "cancellation" similar to radiation in a balanced
feedline, would be pertinent.


Ed