I think you could read Gordo's comments as intending to say there is
more efficiency, and hence more signal power radiated at the optimum
(low angle for a vertical), if you have a good near field ground. The
reflections off ground beyond the Fresnel Zone, (2 t0 5 wavelengths away
from the antenna), are what control what low angle you achieve for the
longer distances. In other words, what is the ground condiiton well
beyond your yard, where the first reflections happen from your antenna?
This is not to be confused with reflections that might happen in the
near field because your ground mounted vertical might be lower than the
surrounding surfaces, or close to other reflecting or blocking
conductive surfaces.
It would help if Gord had been more precise, or given more explanation
to avoid multiple interpretations.
At our local club, this week, we had a guy give the basics of Antennas
from a point of view I have never seen expounded, but which is a good
way of looking at the subject. He defined an antenna as a capacitor,
whose plates, (elements) are designed to be most inefficient at holding
energy, and thus, efficient at "leaking" the radio wave to cause
radiation. An interesting way to look at it, and perhaps easier for
some to comprehend. Personally, I have liked John Kraus's approach of
taking a coaxial feeder and opening up the center and shield to form a
dipole. When the two elements are at 180 degrees to each other, you had
maximum antenna effect, if the elements were resonant.
A local also presented a show and tell on the Circular Polarizing phase
shifter needed to use with two crossed dipoles. The purpose based on
the article on page 33 of Dec. 2010 QST, is to enhance your reception
of either circular polarization sense, since the article points out that
all received signals are going to be elliptically, (a case of
circularity) polarized upon ionosphere reflection. Using a phased pair
of crossed dipoles, you can favor the Ordinary Wave or the Xtraordinary
wave.
-Stuart Rohre
K5KVH
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