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Old September 11th 09, 07:03 PM posted to rec.radio.amateur.antenna
Richard Fry Richard Fry is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 440
Default Spherical radiation pattern

On Sep 11, 11:47*am, Art Unwin wrote:
There has been some "talk" that the spherical radiation pattern shown
via Poynting's vector is impossible or just a theoretical thing. etc etc


Quoting from John Kraus' well-respected textbook "Antennas For All
Applications," 3rd edition, page 74: "Although the isotropic source
is convenient in theory, it is not a physically realizable type. Even
the simplest antennas have directional properties, i.e., they radiate
more energy is some directions than in others."

The Poynting vector does not apply only to isotropic sources. Here is
a link to a simple definition: http://www.britannica.com/EBchecked/...oynting-vector
.. It doesn't have to describe a perfect sphere. And in fact for
practical, physical antennas it never does so.

FYI, Art, nowhere in that textbook does Kraus write anything about
your equilibrium, tipping, Coriolis effect, or tank circuits, or their
being germane to the proper understanding and/or functioning of
antennas.

RF