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Richard Clark · October 24th 08, 08:14 PM posted to rec.radio.amateur.antenna

On Fri, 24 Oct 2008 07:16:49 -0400, (J. B. Wood)
wrote:

Hello, Richard, and all. And as I previously pointed out the 2-port model
might not be the equivalent of a line in a broadband sense. Another way
to put it would be that the 2-port could have the electrical
characteristics (characteristic impedance, delay, loss) of a particular
line at one frequency but of a different line at another frequency.

Hi John,

Your statement above is as much a rambling philosophy as you argue I
write. The difference is in pride of authorship alone.

Please excuse my snipping of the remainder of your comments but they sound
more of philosophy than science and quite frankly I have no idea what
you're talking about.

We can agree your motivation wasn't to go there. Some little portion
of this is going to be about that motivation.

You emphatically stated an antenna "IS" a
transmission line without a few words on why this should be so.

Again, a contradiction. You note my brief statement, and then you
complain of length - "without a few words" which is as archaic a
construct as any I've employed. In light of charges of rambling
philosophies, I enjoy irony too. It is very hard to answer a "damned
if you do, damned if you don't" rebuttal, so I pursue your semantics
that invite their focus.

My take on a transmission line (or waveguide) is that it is a medium
(ideally lossless) used to convey electromagnetic energy from one place to
another. An antenna (or antenna array) is used to introduce or extract
electromagnetic energy from a medium.

A transmission line is not a medium in the strict usage of the term
medium. Terms are important, or they become your own philosophy. The
Æther fully qualifies under your application and it is multiport
beyond count. So, predictably, this medium you speak of fails upon
the basis of exhibiting more ports than is necessary.

Perhaps "fails" is too strong, but it is enough to note that your
inclusion stumbles against your premise at the top of this quote.

Now, if you meant that antennas and transmission lines share phenomena
in common (e.g. standing waves) that would be a correct statement.

I generally write what I mean. I take responsibility for it. If
there is doubt, then a question offered will erase that in following
rounds of discussion. Volunteering tea leaves reading only adds to
the murk.

And
Maxwell's equations certainly apply to both. But I don't see an
equivalency of a single antenna and a non-radiating (at least intended by
design) transmission line and I don't recall any of my many
electromagnetics texts making such a statement. Sincerely,

That is why I offered three sources (posted twice in this thread) that
speak to the matter at great length and with enough elaboration in
math to resolve problems of what you complain of in my "philosophy."

So, as popular culture maintains that "the third time is a charm":
On Tue, 21 Oct 2008 08:23:32 -0700, Richard Clark wrote:

Institutional memory here is so slight:

"Theory of antennas of arbitrary size and
shape," Proc. I.R.E., 29, 493, 1941 and S. A. Schelkunoff, "Advanced
Antenna Theory, " John Wiley and Sons, Inc., New York, (1952)

Accessible reference work can be found by searching the PTO with his
patent number: 2235506.

I am happy to parse philosophies expressed here, but a visit to the
PTO would serve informed discussion far more. Schelkunoff expressly
chose to extend the transmission line into antennas for a very good
reason, and that reason has served conventional antenna design quite
well.

73's
Richard Clark, KB7QHC