The above antenna does not have a ground plain such that it is
unbalanced.
If the feed line was buried underground for a distance at least a half
wave long
would the external current on the feed braid leak to earth/ground
where the transmitter
itself would see no interference from the imbalance? A test for this
I suppose is
rubbing your hand over the coax at the transmitter site to see if any
swr variation occur
Art