There is indeed a "return path" for a single wire. The wire
capacitively couples back upon itself, and the dielectric affects that
capacitance. That may sound strange, but think of a capacitive hat
loading at the top of a vertical or at the end of a dipole. The wire
itself is just a different geometry and therefore has less effect, but
it's the same principle.
EZNEC+ is based upon NEC2 and simply allows more wire segments than some
other versions. I can't say whether or not NEC2 handles dielectrics, or
whether W7EL added a calculation on his own, but if you define a
dielectric in EZNEC+ it will result in a shorter wire for the same
effect as a bare wire. That at least fits the physics of the situation.
Dave AB7E
On 9/20/2022 6:36 PM, Edward McCann wrote:
I’ve been looking for several decades for a technical analysis of the Vf of a single
bare and insulated wire, hearing nothing but lore from just about everywhere, unbelievable
proposals and formulas from some, exhortations from academics that such a search is
pissin’ in the wind, since there is no return path, as there is in twin lead or in
coax.
73
Ed McCann
AG6CX
Sausalito
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