https://i.postimg.cc/8k2w1vDW/ant.png
This models a 20-meter dipole 20' above ground with a common-mode
current path. The vertical wire, which is connected to one side of the
feedpoint, represents the coax shield. At 1' it runs horizontal for 25'
to the transmitter, which is not grounded. 15' from the transmitter the
shield connects to ground. You can see the current in the ground wire as
a short vertical yellow trace to its left.
The ground decreases common-mode current heading toward the transmitter,
but not by a great amount for this geometry. I picked the dimensions
just to get a nice screen image, not to minimize shield current. The
current in the ground wire is about three times that in the wire that
heads to the transmitter.
Brian
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