> As I am sure you are aware, it's not only the close-in ground system
> that affects the effectiveness of the vertical, but the conditions in
> the Fresnel zone as well. Most amateurs are not in a position to do
> anything about the latter, as it is outside the boundaries of their
> property. The soil conductivity in WA is not terribly high, so the
> ground reflection will be very different from that found in an area
> such as yours.
ZL3REX works out much better on an inverted L than on a low
horizontal. He lives in a valley without particularly good soil
between high mountains, and has 30 radials on a 70 foot high
Inverted L. Not a particularly large system, but it is in the clear from
other antennas, masts and towers.
VK3ZL (also in a poor soil area) works out about evenly comparing
a dipole at 100 feet or more and a 40 foot radiator with partial coil
loading and a whip at top, and the rest of the loading at the bottom,
when conditions are good. He has about 20 or 30 radials. When
conditions are poor, the vertical is generally better.
I'm afraid there are far too many variables for us to reach any
conclusions by looking at even dozens of stations unless they had
nearly ideal antenna systems in the clear.
The problem is we have no idea what the efficiency and pattern of
any of the antennas is, unless we compare large full size antennas
over what we know are efficient ground systems with more than 50
1/4 wl radials.
When we stuff a few antennas within a few hundred feet of each
other on 160 for a comparison, we have little idea what is radiating.
A large part of the results depend on the time of day we operate,
and the conditions. When conditions are marginal my vertical
smokes all the other antennas. When conditions are wide open, or
peaking, and at times during geomagnetic storms, a low dipole can
come very very close (but never quite as good) as the high dipole
and vertical.
> reporting his findings after those steps. We all have to accept that
> a general rule which works for most people, may not be universal.
That is very true, and it is mostly decided by what happens to be
wrong that we can't for some reason correct. I doubt it is soil or
propagation, because there are too many good working systems in
areas of poor soil.
I think one reason verticals dominate in some locations is the
users have room for ground systems and space to keep antennas
apart and away from other vertical structures.
73, Tom W8JI
W8JI@contesting.com
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