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Old November 2nd 14, 10:30 PM posted to rec.radio.amateur.antenna
gareth gareth is offline
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First recorded activity by RadioBanter: Sep 2012
Posts: 1,382
Default Short antennae, et al

"gareth" wrote in message
...
I get the impression that I am trying to maintain a discussion
with some whose knowledge and understanding is way below the
level at which I am discussing, and that it is their limited grasp
of technical matters that results in their infantile outbursts when
the shaky premises of their (almost religious) beliefs are
threatened.


This continues to be illustrated tonight. A changing electric
field produces a retarded changing magnetic field, and a changing
magnetic field produces a retarded changing electric field. One
cannot exist without the other, as demonstrated by Maxwell's Equations.

(And this is where the thinking behind the crossed field antenna was wrong,
because the changing electric field produced by the capacitor plates
produced the retarded changing magnetic field at all points in the same
space,
and it was unnecessary to introduced the (short antenna! (qv)) attempts
at producing the changing magnetic field.)

In the balanced transmission line, there are two travelling electromagnetic
waves out of phase with each other. Where some people are confused, and
their confusion gives way to infantile outbursts, is that the superposition
of the
two fields results in nearly total external field nullification resulting in
little, if no, radiation
and little, if no, near fields. However, both of the electromagnetic waves
continue
to exist and are guided by the two wires of the feeder.

In the case of coaxial feeders, the electromagnetic wave exists in the
dielectric.

(Let's not even get round to discussing slot antennae or dielectric
antennae, their
being no conductors in either case! :-) )