Thread: Image theory
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Old December 22nd 06, 06:36 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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Default Image theory

On Fri, 22 Dec 2006 10:08:03 -0800, Richard Clark
wrote:

On Fri, 22 Dec 2006 17:44:41 -0000, "David" nospam@nospam wrote:

But the academic books on Antenna theory written by Professors of
Electromagnetics all use image theory for vertical monopole antennas
including those with elevated radials. Can anyone quote an antenna theory
book that does not?


Hi David,

The objection arises out of your commingling radials in the discussion
where the dons never asserted an image theory for them. Can you quote
any source that does? (Let's try proving a positive.)


Let's just cut to the chase, vis-a-vis radials. These elements serve
to balance and match, not to propagate (in the sense of ground
reflections). In fact, when all the radiative contributions of a
ground plane (radials in a plane) are considered, they are self
negating.

If we were to consider the aspect of this image theory (reflection of
a wave); then those radials would have to consume both a lot of
distance out from the feed point, and a lot of real estate. By any
standards found in the market place, or in implementation, this is so
rare as to be exceedingly exceptional. Commercial AM antenna radial
fields DO NOT come close to this either.

73's
Richard Clark, KB7QHC