G3XZX wrote:
Am I correct in thinking that because a full-sized dipole or other
very large antenna, at a sufficient height, will have a different
radiation pattern from a short monopole, 1 watt ERP from each antenna
judged by field strength measurement at the same location will give
rise to different field strengths at various other distances because
the sum of sky and ground wave effects changes differently with
distance for the two antenna types?
Well, here we get into the very muddy waters of just how you
measure ERP - seemingly a very imprecise science. Also the far
more interesting area of matching the antenna to the propagation
medium (sometimes referred to as ionospheric matching). An
example of this is the idea that a "useless" horizontal antenna - or
the horizontal part of an L - can in some cases give an improvement
on the pure vertical because of the way the signal is presented to
the ionosphere. And this is another area where the unreliability of
the technique makes it a taboo area for the commercials but a
potential source of gold for us.
Isn't radio fascinating?
Mike, G3XDV (IO91VT)
http://www.lf.thersgb.net
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