Opinions of the many individuals depend on geographic lattitude, World
population densities, what bands happen to be favourites, G5RV's and
how much money there is in the bank. Let's try to remove these
distracting factors.

I'll put it in somewhat different "simplistic" terms.

Everything else being equal, the deciding factors are geometry and
trigonometry. The performance of a dipole is better at elevation
angles greater than about 45 degrees and the performance of a vertical
is better at lower angles. That's because the vertical and horizontal
antenna types are oriented at 90 degrees to each other. At elevation
angles around 45 degrees performance is about the same for both types.

The ground path distance corresponding to 45 degrees depends on height
of the ionospheric reflecting layers. Layer height depends on which
layer, mainly E or F2, day or night, summer or winter, and the solar
sunspot cycle.

(None of these important factors are taken into account by antenna
modelling programs. Propagation prediction programs DO take them into
account but, with them, geometry is also an essential factor.)

The range of distances at which vertical and horizontal antennas have
similar performances in daylight is from 140 miles (E-layer) to 500
miles (F2-layer), which falls to 370 miles at night.

But what decides whether a transmiiting antenna will be used or not is
NOT the distance to the receiver - it is the MUF (maximum usable
frequency)

The MUF is geometrically-derived which increases with distance and
with a decreasing elevation angle. It also changes with geographical
lattitude and sun angle. With the F2-layer the MUF can increase by 3
times the vertical critical frequency Fcrit. Thus, by using a vertical
low-angle antenna there are more bands and potentially more listeners
available.

Fcrit is the highest frequency which is reflected from a layer at
vertical incidence. At higher frequencies the wave passes straight
through. The MUF for high radiation angles and short distances is
therefore low. It does not increase very fast as the radiation angle
falls. It varies with night and day and the solar 11-year cycle. For
the E-layer in summer daylight Fcrit is about 3.5 MHz. For the
F2-layer in summer daylight it is about 6.5 MHz and about 5.5 MHz at
night. On winter nights Fcrit for the F2-layer is about 3.5 MHz.

Fcrit and high angle MUF's are subject to variation due to solar
activity. But in general only the 80m and 160m bands, and sometimes
40m, are open for short distance rag-chews. This restricts the
advantages of high-angle horizontal dipoles.

Finally, a horizontal dipole radiates best when broadside on. Unless
it is rotateable it has weaknesses in its service area.

If I had to choose, I'd always choose a half-wave 80m vertical in
preference to a half-wave dipole.
----
Reg.