"Reg Edwards" wrote in news:drqije$rqq$1
@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com:

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.

No, at 45 degrees the PATTERN is about the same (assuming that the
horizontal antenna is at least .25 wavelength high). But the actual GAIN
over an isotropic source is equivalent down at around 25 degrees. That's
because the vertical is normally a monopole, the other half of which is
reflected in the ground, whereas the dipole is a dipole and its ground
reflection is therefore another dipole stacked with it. Ground losses
for the dipole occur at a lower incident angle and further from the
antenna and are thus lower.

Of course, you can have the best of both worlds by using a vertical
dipole, in which case your take-off angle will really be quite low.

The main reason why verticals tend to outperform dipoles on low-band DX
paths is that the dipoles and other horizontally polarized wires are
rarely very high. A lot of them are only about an eighth of a wavelength
up or even less. This increases ground losses at all angles and reduces
the efficiency of the antenna. And if you can get the current loop to
climb up the antenna (by top loading it), a vertical will compete very
strongly below about 30 degrees.


--
Dave Oldridge+
ICQ 1800667