Guy I have ALWAYS thought that the various Computer-based modelling of
Ground and its effect on Antennas is WAY off . . .
And surely the errors are MOST significant on 160m, not just because
Antennas are near the ground (in wavelength terms) . . . but also because
even the ground 130 ft deep is still going to have an effect . . . and there
is no way EZNEC can possibly take that into account, even if you KNEW what
was underneath your topsoil !
In my particular case it's not the effect on Verticals on 160m that interest
me . . . it's the effect on a Low Dipole.
Any DX stations I work on 160m will confirm I put out a pretty respectable
signal . . . my signal reports around the world and more recently I am able
to compare my RBN Reports across NA and they tend to be very similar to the
other British DXers.
However, most people are surprised to discover that for the last 50 years I
have always used a Horizontal Half Wave dipole on 160m, at around 50ft.
BUT I believe that EZNEC plots showing that most of the RF is just very High
Angle is WRONG . . . that's because in practice the Ground underneath it is
rubbish . . . so the Dipole's effective height above Ground is much higher.
And in fact, it seems that most people who have Dipoles on 160m mounted over
or near a very comprehensive Radial system DO get poor results using them
for DX . . . but that goes to confirm my theory (which is all based on my
actual experience on Top Band)
Roger G3YRO
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