"christofire" wrote
...

"Szczepan Bia³ek" wrote in message
...

-- snip --


* Would you care to cite a reference where it is stated that EM waves
in the far field of a transmitting antenna contain a significant
longitudinal component? Many respected authors, such as Kraus, have
illustrated the contrary, but their work isn't limited to paper;
people like Kraus have designed real antennas of types that are still
in use today.

Maxwell ASSUMED that the aether is a solid body and ASSUMED that there
are the transversal waves. Next he do the math to it. To prove it he
asks Michelson to measure the movements of the Earth in this solid
body. In 1878 (about) Michelson did not detect 30km/s. In 1925 he
detect 0.4 km/s. It means that the eather is not a solid body. The EM
theory is only math (a piece to teach).

* You haven't cited a reference. The words you have written here do not
demonstrate that EM waves are longitudinal. A 'reference', if you
didn't understand the term, means a passage from a book or paper written
by someone who has a proven reputation for good, useful work in the
field.

" Oliver Heaviside criticised Helmholtz' electromagnetic theory because
it allowed the existence of longitudinal waves" .From:
http://www.answers.com/topic/hermann-von-helmholtz

Do you know somebody who has more proven reputation in acoustic and
electrodynamics than Helmholtz?


* Yes: the late John D Kraus. He was a practical engineer as well as a
theoretician and his native language was English. He managed to put into
practice a lot of the theory that others had written about and he recorded
his work lucidly. I've already named two of Kraus's books - can you cite
something written by any of your favourites that provides clear
explanations that you understand? Answers.com doesn't explain anything
technical.

For practical engineers the math theory is useless.


Hertz was the pupil of Helmholtz.
The Maxwell's equations (that from 1864) was the same like the Helmholtz'
for fluid mechanics.
Many textbooks inform us that it was a big Maxwell's mistake. He ignored
atomic nature of electricity disovered by Faraday at electrolise.
Helmholtz not ignored it.
Maxwell (modified by Heaviside) is only a piece to teach the math.


* Heaviside's documentation is appaling! I remember going through a
catalogue of his work in an effort to get to the truth about the origin of
the 'Heaviside condition' - a lot of it was written in obfuscation babble,
a bit like some of the contributors to this group.

He is the father of the hydraulic analogy where the electricity is the
incompressble masless flud.
Electrons in antenns are compressible and have mass. What is electricity in
J. D. Kraus?


Sound waves are longitudinal because air pressure is a scalar,
whereas electric and magnetic fields are vectors - they have
polarisation.

The math has not to do here.

* What 'math'? ... just the mention of scalars and vectors, in a group
devoted to antennas. Please.

The first step should be dicovering which part of the oryginal Hertz
dipole radiate:
http://people.seas.harvard.edu/~jone...Hertz_exp.html

The big sparks (current) or the plates (balls).
Note that todays dipoles are quite different. Now no current between
the tips.


Here is the full acoustic analogy. The two loudspeakers work like the
two monopoles.

* Rubbish. What 'two loudspeakers'? Ever heard of a horn
loudspeaker? ... it produces longitudinal pressure waves.

Why then the two loudspeaker and the two monopoles have the same
directional patern?

* What 'two loudspeaker'? If you're drawing comparison between a
direct-radiator loudspeaker and a dipole and using that as a basis for
saying that EM waves are longitudinal, as I suspect you are, then you
should also consider a horn loudspeaker. Sound is radiated from the
mouth of a horn 'speaker and the other side of the compression driver
diaphragm can be totally enclosed. There is no simple comparison with a
dipole antenna in this case.

The horn is a monopole. See:
http://paws.kettering.edu/~drussell/Demos/rad2/mdq.html
The unboxed loudspeaker is a dipole.

* Why don't you look into horn louspeakers and then report back. You may
find them fascinating and very unlike dipoles.

Like fascinating is the two monopoles antennas (your dipoles).
S*

Chris