On Oct 2, 12:58 am, Bill Horne wrote:

What puzzles me is the ground: I don't understand why such a wire would
function as anything but, well, ground. I

I think it's really about ground (dirt) conductivity. Which varies all
over the place.

In some places (moist, loamy soil with lots of minerals, coastal areas
where the water table is very high and salty) the dirt is a pretty
good conductor, to the point where antennas "worked against ground" do
pretty well with just a ground rod or two. RF just bounces off that
sort of dirt.

In other places (dry, sandy, rocky soil) the dirt is a very lossy
counductor, and acts more as an RF absorber.

With a low dipole, the ground is so close that it has major effects on
the antenna. If it's lossy dirt, it just soaks up RF, but if it's a
decent conductor, it can act as a reflector. The added wire is just a
way of improving the ground conductivity in the dirt that is most
involved: the dirt directly under the antenna.

73 de Jim, N2EY