Richard Clark wrote:
On Fri, 25 Jan 2008 04:13:56 GMT, Gene Fuller
wrote:

The irradiance equations
work fine for detailing the external effects, but they don't give any
hint of what happens inside the interface. Think Thevenin.

Hi Gene,

Cecil isn't going to rise far enough to catch a breath of air on this
one. You may as well drop the shoe for lurkers (and me).

I don't see the connection to Thevenin (specifically); but, for me,
inside the interface we can draw the correlation of TIR failure (the
chapter that Cecil hasn't drug across the Xerox yet) to evanescent
waves to near fields to how antennas work.

73's
Richard Clark, KB7QHC

Richard,

Perhaps I have misread the message traffic for the past 5 years or so,
but it appears that most of the heat over wave reflections is about what
happens during the reflections, including detailed concern about energy
and momentum. The issue is never (or at least rarely) about what one
would find in external measurements on the transmission line (or free
space, as the case may be). This goes back at least to the battles
between Steve Best and Walt Maxwell. (I pointed out that both models
were correct, although they arrived at the proper conclusions in quite
different manners.)

More recently, we have great battles over interferometers and cute Java
demonstrations. Absolutely nobody would question the overall wave
superposition principles shown in the FSU Magnet Lab Java applet. Most
people know how to add sine waves, or at least they can look up the
technique. The entire debate usually comes down to arguments about how
that addition actually takes place physically. This is what I am calling
the Thevenin equivalent. In particular, the external observations are
unambiguous and non-controversial. The standard models and equations
give all the correct answers for the observables. At the same time those
models and equations say nothing about how the two FSU input waves
suddenly jump together to superpose and interfere. Do the waves
"cancel"? Is there a requirement for auxiliary waves that are created
and immediately destroyed? How does one account for missing momentum?

That attempted under-the-hood analysis with tools suitable only for
external description drives my suggestion of the parallel to the
Thevenin model.


73,
Gene
W4SZ