Richard,
Is that you, or did your evil twin steal your role on RRAA?
Try reading my comment again. If you still disagree, then perhaps you
should crack open any elementary physics or optics textbook.
I did not mention antennas or lobes. I was commenting on your assertion
that the horizontal polarization is "shorted out" at a conducting
surface. Utter nonsense.
73,
Gene
W4SZ
Richard Clark wrote:
On Wed, 05 May 2004 22:38:06 GMT, Gene Fuller
wrote:
Richard,
Are you sure you meant the statements quoted below?
Horizontal polarization bounces just fine from "horizontally conducting
surfaces". Indeed, when a mixed polarization wave hits a conducting
surface the horizontal polarization in the reflected wave is enhanced,
not "short-circuited". This is the same phenomenon that is the related
to Brewster's angle.
Perhaps you really meant to say that a special guided wave mode, namely
the ground wave, does not support horizontal polarization.
73,
Gene
W4SZ
Richard Clark wrote:
[Lots of more or less correct stuff snipped]
A horizontally polarized antenna seeing a horizontally conducting
surface is a scenario that describes a self-short-circuit.
Horizontally polarized waves meeting the earth (a conductive one)
immediately snuff themselves (how long would your car battery last
with a screwdriver held across its poles?).
Hi Gene,
Vertical polarization is the only mode that the Brewster Angle works
for (that's why polarized sunglasses work so well, they are
contra-polarized for what DOES reflect).
To test your hypothesis, use EZNEC over a perfect ground and note the
distinct difference at low angles (less than 5 degrees). The
horizontal radiation lobe is an example of Lambertian (another Optics
term) distribution where the maximal gain is observed directly
overhead, and only when phases positively combine (due to the high
surface conduction presenting a second source). Other phases give
rise to this Lambertian distribution which is much like the lobe
characteristics of a headlight glowing in the fog.
73's
Richard Clark, KB7QHC
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