Roy Lewallen wrote in
:

....
The point I was hinting at is that calling ground plane radials
"ground" doesn't impart magical properties to them. They are
conductors with current flowing on them, so they create fields like
any other conductors with currents. And the total current flowing in
the radials is equal to the current flowing in the top wire.

.... if you assume that no current flows on the feedline / mast, and it
seems that doesn't happen by accident.

Owen