"christofire" wrote
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"Szczepan Białek" wrote in message
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"christofire" wrote
...
"Szczepan Białek" wrote in message
...
"Mike Coslo" wrote
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Art is trying to convince us that EM energy is also a mechanical
force, consisting of particles that fly off the end of our antennas
like little turds. The ramifications of that means that everything we
thought we know about RF - and in fact all physics is completely
wrong.
You have made a small mistake. Antennas are feed with the oscillating
voltage. So the little truds fly off and come back. It is normal
longitudinal wave.
The key problem is what radiate: the end of an antenna or something
else.
What do you think?
S*
No, you've made a mistake ... again. EM waves are transverse waves in
air (i.e. around a normal antenna) not longitudinal waves (see
http://en.wikipedia.org/wiki/Longitudinal_wave).
EM waves by Maxwell are transverse waves. They are the paper waves. The
real electric waves are mainly longitudinal.
* 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).
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?
Also, antennas that radiate are fed with alternating current. The
terminal voltage is almost immaterial in comparison with the current -
that's what causes the radiation.
If you want to discover what radiates I suggest you read one of the
normal text books on the subject, like Kraus 'Antennas', and stop making
up your own versions!
To discower what radiates will be better to do experiments with tipping
of monopole antenas.
* Where do you get this stuff from? Please visit a library - you could do
yourself a lot of good.
Now Maxwell is avaiable on line. It is interesting to take a glance at them.
S*