Richard Clark wrote:

Roy and others have answered this one in the past too. You employ the
near field table to observe the ground wave. It works approximately
well, even out to the edge of the implicit flat universe. If you
object to flat universes, you are no longer in the realm of ground
wave. If anything, modelers give MORE response in comparison to the
BL&T data.

With EZNEC, you have to use the near field analysis to include the
ground wave; direct ground wave analysis isn't included in EZNEC because
it's of very limited use to most amateurs. In fact, it's really of
interest only to AM broadcasters and a very few other very small and
specialized users, who just about universally use EZNEC Pro which does
include direct ground wave analysis.

But anybody who's interested in direct ground wave analysis can also use
one of the other modeling programs which includes it, or use NEC-2
itself, available free from http://www.si-list.net/swindex.html. The
manual is available there also. NEC-2 produces field strength data
including the ground wave if requested with the proper entry on the RP
"card".

Roy Lewallen, W7EL