I want to erect a full-wave horizontal loop antenna for use around 3.5
mHz (as an NVIS antenna). The problem is, I don't have quite the
space to configure such an antenna, which would be somewhere around
280 feet long using normal wire. (Don't have my actual calculations in
front of me, but they are roughly these dimensions).

I've gotten the idea that I could shorten the physical requirement, by
using RG-58 coaxial cable instead of regular wire, and taking the .66
velocity factor into account--- turning an electrical length of about
280 feet into only around 180 physical feet of RG-58. (I have a 1000-
ft reel of this stuff). It would be fed with 300 ohm parallel lines
to an antenna tuner.

The questions, to those who may be more well-versed in the theory of
antennas, are 1) is my reasoning on the V.F. sound? and 2) if I
construct this, should I use the center conducter of the cable as the
active element, or the shield, or connect them together? and 3) Would
the shielding on the cable have any effect on the center conductor
being used as the antenna element?

JP