Ralph Mowery wrote:

I don't work the low bands enough , but I would have thought someone would
have just gave some prctical experiance instead of all the NEC stuff. Not
many hams are going to put up a 60 some foot vertical and the required
ground system for 80 meters.

Could not someone say that with horizontal dipoles about 30 feet up (or
whatever is being used) you may get so many miles ground wave and during
the day so many miles skywave and so many more at night ?

The basic problem is that there isn't a simple answer to your question.
Any simple answer you'd get would be wrong much or most of the time.

It's safe to say that you won't get any ground wave communication at all
with a horizontal antenna, unless a vertical feedline is radiating. The
range with a vertical antenna depends on the noise level, which changes
day to day, season to season, and day to night, as well as ground
conductivity and power level. The ARRL Antenna Book gives a "typical"
ground wave range of around 60 miles at 3.5 MHz, but of course this
depends on the factors I've mentioned, among others -- it's one of those
"simple" answers.

Sky wave communication range depends on the condition of the ionosphere.
Sometimes you'll be able to communicate hundreds of miles, sometimes
zero. There is no range you can depend on. If you're interested in the
performance of a low dipole on 80 meters, I highly recommend _Near
Vertical Incidence Skywave Communication_ by Fiedler and Farmer.

NEC and other programs are fine for predicting the coverage, but it does not
take into account all the variatables that can be answered by the
experiance of actual operations.

Unfortunately, experience doesn't take into account all the variables
either. No one or group of people have experience with all possible
antennas, ground conditions, ionospheric conditions, and noise levels,
so one person's experience is likely to be different from another's.
The value of modeling is that it allows you to see which factors are
important and in what way, so you can get a better idea of what
performance you might get under your particular set of circumstances --
rather than someone else's.

Roy Lewallen, W7EL