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Old September 12th 06, 08:55 PM posted to rec.radio.amateur.antenna
Peter O. Brackett Peter O. Brackett is offline
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First recorded activity by RadioBanter: Aug 2006
Posts: 50
Default Is antenna a transducer to 377 ohms?

Richard:

[snip]
To how many places? Your question is rather oblique when we are
discussing near fields and antenna as "transducer" [not a choice of
term I subscribe to].

[snip]

OK, ok... you've busted me...

I admit that circuit theory is on really shaky ground.

Although circuit theory was developed by Ohm, Kirchoff and others before
Maxwell presented the world with his celebrated equations, we can all agree
that circuit theory is a very poor (one dimensional) approximation to field
theory. Circuits are a thoroughly useless affair dealing only with poorly
understood approximations to the "real deal"...waves!

I admit it, there is no such thing as "voltage", which after all is only the
value V of a definite line integral of the vector field that depends upon
the somewhat arbitrary path of integration, chosen by the integrator,
through the appropriate E field, and so consequently there is no such thing
as a "real" driving point impedance Z = V/I. The only reality is the
characteristic or wave impedance! There I've said it!

So... youv'e got me... I agree... we should not really be messing about
trying to define phoney "transducer" functions between circuit theoretic
variables (V, I) and wave theoretic variables (E, H) since the former have
such an ephemeral existence.

Still in all... one wonders... do circuits and waves, charge particles
(electrons) and waves particles (photons) have any truck with each other
or... do they lead entirely separate lives? What would you call the
intermediaries between reality and approximation?

I'm very sorry to have brought up the subject... I've probably confused the
OP, and I am here and now prepared to recant my heresy, before you light the
kindling beneath my feet, heh, heh... I solemly swear that an antenna is not
a "transducer" between circuits and waves! (grin)

But... ahem... the sun still has spots!

Kathy, bring me another glass of that Rivaner!

Molly Bloom indeed!

--
Pete K1PO
Indialantic By-the-Sea, FL

I seriously doubt that you've unhinged from the origins of that value,
however, it bears only tangentially on the matter.

That is an antenna itself has no effect on the fundamental u and e of
the
media in which it is immersed.

Wrong.

[snip]

Surely uo, eo, Zo and c (velocity of light) are fundamental and invariant
properties of "free space", no?


And some toothpaste makes our teeth whiter, no? Your reply does
nothing to answer your error, however.

[snip]
After all the antenna is very small, and free space is very large
(grin),
and so a tiny antenna cannot change u and e everywhere!

Abstracting from near space to everywhere is the source of your error.

[snip]

No, I'm "contracting" from outer space to near space... using the
contravarient tensor!


Then you have misapplied it, clearly. Arguing does not take the place
of easily demonstrable facts. AH! forgive me, wrong forum, arguing
is classic substitution. However, the entertainment value is rather
poorer this round.

There might just also be plane waves passing through identically the
same
region of space, say emanating from a more distant antenna.

Wrong.
[snip]


Oh, and here I thought that at least tiny remnants of all radiation
eventually passes through every part of space, filling all of space as it
expands throughout the Universe..


Are "thoughts" related to "beliefs?" Bloated speculations of
background radiation don't change the basic assertion that in the near
field, there is nothing that remotely approaches the presumed 377 Ohm
specification. You've both (earlier) acknowledged this and (have
since) challenged it with a semantic fog such as:

I know that Special Relativity [Maxwell's equations] is not supported in
full by General Relativity, but surely even though space is warped by
mass,
superposition must still be supported. The radiation in your
neighbourhood
is a superposition of suitably delayed and reduced (by path attenuation)
of
all radiation, no?


EZNEC demonstrates the violation of your "beliefs," yes?

I miss Reg Edwards already :-(


Certainly you're a poor substitute for Punchinello. (and Kelvin is
winding up a pitch to wing a chunk of chalk off your noggin.)

73's
Richard Clark, KB7QHC