There are some in our group who really, REALLY think that the vertical
is the way to go, and I need some debating points. So, if I had a
decent ground-mounted vertical, should I expect to get the ground wave
distances that G4FGQ indicates in his calculation program?

Is there any area / radius that would be covered by a ground-mounted
vertical that wouldn't be covered by an NVIS horizontal (assuming that
we're operating below the critical frequency)? I have always assumed
that by the theory behind NVIS, the answer would be no... NVIS should
cover everything out to a radius well beyond groundwave distance.
But, I suppose we could install NVIS antennas AND verticals and switch
between them to see which one works best at any given time. Does seem
to be a wasted effort but WDIK?

While I'm at it, how do I estimate antenna efficiency? What is the
average range of efficiencies normally seen with a quarter-wave
ground-mounted vertical, with an adequate ground radial system, in
average soil?

Note that radiation from the end of a low dipole is vertically polarized.
Antenna efficiency, and surface wave field strength, can be computed
with NEC.

Frank, VE6CB