Dave Shrader has kindly contacted me to tell me I was wrong with my
resistivity definition.

Dave is right.

The formula I was trying to remember is:

Resistance = RESISTIVITY x length / area

I goofed and I`m sorry.

Best regards, Richard Harrison, KB5WZI

"Gene Fuller" wrote in message
...
Cecil,
You appear to misunderstand that it is essentially impossible to do
anything with all of your interfering component waves except wave your
hands and flap your gums about them.

you must be new here... that is what these guys do all day long!

Hi Walt,

I am quite surprised and disappointed that you commented on my review of
Steve Best's QEX articles in the manner quoted he

On Thu, 11 Mar 2004 09:17 Walter Maxwell wrote:

And it also totally supports your argument with Gene, who apparently
doesn't get it either, because I heard him claim that Steve's article is one of
the most illuminating and definitive he's read. Unfortunately, Steve's QEX
article is total BS.

Walt, kW2DU

************************************************** *

Here is an exact quote from my email to you dated January 31, 2003.

Hi Walt,

I'm back.

I have re-read the Best QEX article, I have read your rebuttal
carefully, and I have re-read parts of Reflections II.

I have to say that I believe the QEX article in question is fair and
correct. I cannot find a single flaw in it.

I have documented my response by adding comments to the rebuttal draft
you sent me the other day. My comments are in red.

In summary, I think the QEX article is completely correct in items 1, 2,
and 3. I am less comfortable about making any sort of definitive
statement on item 4.

I have been aware of the controversy for some time, and I am somewhat
dumbfounded by the entire matter.

I tacitly believed that all of this stuff had been fully defined,
understood, and non-controversial for many decades. Certainly there is
no new science in classical transmission line theory in 2003.

To the best of my understanding this entire matter has somewhat the
character of a tempest in a teapot. I have not found the slightest
evidence that your model and Steve Best's model disagree in any
measurable way. Clearly the insides of the models are different, but the
visible, measurable parts are not.

Is there a single case in which Best's model gives the wrong answer by
any measurement technique?

Is there a single case in which your model gives the wrong answer by any
measurement technique?

From a visualization and conceptualization point the models are quite
different. You note that many engineers appreciate your model as it
provides them a good understanding of the reflection behavior. To be
brutally honest, I prefer the approach taken by Best. I like the
equations to balance explicitly, and I am less comfortable with relying
on concepts like virtual opens and shorts.

Again, I do not see any physically measurable difference in the output
from the models. The rest is philosophy.

snip of irrelevant pleasantries

************************************************** *

Soooo, Walt, what did I write that elicited your unkind comment?


73,
Gene
W4SZ

Cecil,

OK, I will 'see' your references and 'raise' my bid to Born and Wolf
"Principles of Optics", 7th edition.

I recommend section 1.6, "Wave propagation in a stratified medium.
Theory of dielectric films". This section runs from page 54 to page 74,
and it describes in full detail everything you would want to know about
propagation of waves in multilayered structures.

There is a disclaimer in the introduction to this section which says,
"For the treatment of problems involving only a small number of films it
is naturally not necessary to use the general theory, and accordingly we
shall later describe an alternative and older method based on the
concept of multiple reflections." The reference is to section 7.6
"Multiple-beam interference", which runs from page 359 to page 409.

Similar sections are included in the 6th edition of this book, on pages
51 to 70 and 323 to 367 respectively. I am sure you can find one or both
of these editions in the TAMU library. I prefer the 7th edition, as it
seems easier on the eyes.

If you choose not to actually read these references I will tell you that
the first section is a full-blown Maxwell's equations treatment, and the
second section employs an interfering wave treatment.

What I find interesting is that there is not one mention of bouncing
energy waves or waves that have disappeared but their energy lives on.
If you read your favorite Melles-Griot material carefully without adding
your own spin (how else could it be, etc.) you will see that they do not
discuss bouncing energy waves either. You will notice that M-G say the
energy "appears" in the transmitted wave. This is good, since we like to
believe conservation of energy is maintained. M-G do not discuss the
mechanism. All of the stuff about bouncing energy rejoining the forward
wave is purely in your imagination.

I think I have finally figured out the root of the disagreement. Your
approach is similar to a one-trick pony. You have latched onto the
concept of interference to the exclusion of any other valid approach. As
a consequence it becomes *necessary* to imagine such things as bouncing
energy waves. The Maxwell's equations approach does not require this
sort of crutch. Try it, you might like it.

I am quite familiar with both analytical methods, and I am comfortable
in using either one. The key is understanding when a given analytical
technique will be the most useful, most direct, most intuitive, and so
on. I have nothing against interference, but its misapplication is like
using a pipe wrench to drive a nail while a hammer is right at hand.

73,
Gene
W4SZ



Cecil Moore wrote:



If that is beyond your comprehension, just say so but, in reality, those
interfering component waves obey the laws of physics as explained in
_Optics_, by Hecht and on the Melles-Groit web page:

http://www.mellesgriot.com/products/optics/oc_2_1.htm

On Fri, 12 Mar 2004 03:51:35 GMT, Gene Fuller
wrote:

The Maxwell's equations approach does not require this
sort of crutch. Try it, you might like it.

Hi Gene,

It's not about being correct, it's about "truth" and proving the great
satan Steve wrong. When you've been flashed fried, facts don't
matter anymore. ;-)

73's
Richard Clark, KB7QHC

On Fri, 12 Mar 2004 03:51:35 GMT, Gene Fuller wrote:

Cecil,

OK, I will 'see' your references and 'raise' my bid to Born and Wolf
"Principles of Optics", 7th edition.

I recommend section 1.6, "Wave propagation in a stratified medium.
Theory of dielectric films". This section runs from page 54 to page 74,
and it describes in full detail everything you would want to know about
propagation of waves in multilayered structures.

There is a disclaimer in the introduction to this section which says,
"For the treatment of problems involving only a small number of films it
is naturally not necessary to use the general theory, and accordingly we
shall later describe an alternative and older method based on the
concept of multiple reflections." The reference is to section 7.6
"Multiple-beam interference", which runs from page 359 to page 409.

Well, Gene, you apparently deny that 'bouncing' waves exist. So what exactly are
'multiple reflections'?

Similar sections are included in the 6th edition of this book, on pages
51 to 70 and 323 to 367 respectively. I am sure you can find one or both
of these editions in the TAMU library. I prefer the 7th edition, as it
seems easier on the eyes.

If you choose not to actually read these references I will tell you that
the first section is a full-blown Maxwell's equations treatment, and the
second section employs an interfering wave treatment.

So I now ask, if your selected reference discusses interfering wave treatment
and multiple reflections in the explanation of impedance matching, then why do
you consider Cecil's position concerning reflected energy joining the forward
wave as purely in his imagination? Seems as if you're wearing opaque glasses
backward.

What I find interesting is that there is not one mention of bouncing
energy waves or waves that have disappeared but their energy lives on.
If you read your favorite Melles-Griot material carefully without adding
your own spin (how else could it be, etc.) you will see that they do not
discuss bouncing energy waves either. You will notice that M-G say the
energy "appears" in the transmitted wave. This is good, since we like to
believe conservation of energy is maintained. M-G do not discuss the
mechanism. All of the stuff about bouncing energy rejoining the forward
wave is purely in your imagination.

Imagination, indeed!

I think I have finally figured out the root of the disagreement. Your
approach is similar to a one-trick pony. You have latched onto the
concept of interference to the exclusion of any other valid approach. As
a consequence it becomes *necessary* to imagine such things as bouncing
energy waves. The Maxwell's equations approach does not require this
sort of crutch. Try it, you might like it.

Gene, multiple reflections in wave mechanics are the basic tools that accomplish
impedance matching--no way are the reflected waves any sort of a crutch. There
can be NO matching of different impedances without reflections. How could there
not be reflections when electromagnetic waves encounter a diffferent impedance
when going from medium to another?

I am quite familiar with both analytical methods, and I am comfortable
in using either one. The key is understanding when a given analytical
technique will be the most useful, most direct, most intuitive, and so
on. I have nothing against interference, but its misapplication is like
using a pipe wrench to drive a nail while a hammer is right at hand.

Wave interference is the total basis for all impedance-matching operations.
There is no misapplication of wave interference, and your assertion that the
pipe wrench and hammer apply here is absurd.

If you have a copy of QEX for Mar/Apr 1998 please review an article there
concerning this subject. It just might give you the opportunity of looking at
the concept from a somewhat different perspective.

Walt, W2DU

Gene Fuller wrote:
If you choose not to actually read these references I will tell you that
the first section is a full-blown Maxwell's equations treatment, and the
second section employs an interfering wave treatment.

Everyone already knows the end results so Maxwell's equations offer no
clues as to what actually happens in reality in the process of
yielding those results. The interfering wave treatment is the only one,
to the best of my knowledge, that yields clues as to the physical events
involved. What happens has to obey the laws of physics including the laws
of interference and conservation of energy and momentum.

What I find interesting is that there is not one mention of bouncing
energy waves or waves that have disappeared but their energy lives on.

Gene, neither have I ever said anything about "bouncing waves". That is entirely
a diversionary invention of yours. I have talked about reflected waves, Dr. Best
has talked about reflected waves, and the Melles-Griot web page also talks about
reflected waves. You are on record as asserting that reflected waves don't exist
thus disagreeing with Melles-Griot. Have you ever used a TDR?

If you read your favorite Melles-Griot material carefully without adding
your own spin (how else could it be, etc.) you will see that they do not
discuss bouncing energy waves either.

Neither have I ever discussed "bouncing energy waves". That is your very
own diversion from subject matter that you are apparently loathe to discuss.
The Melles-Griot web page indeed does discuss destructive interference between
two rearward-traveling reflected waves, the "lost" energy of which, winds up
traveling in the forward direction toward the load.

You will notice that M-G say the energy "appears" in the transmitted wave.

Is that anything like angels appearing to the Virgin Mary? :-)
"Appears", in the M-G context means "coherently joins".

How does the "lost" energy from two interfering rearward-traveling waves
appear in the forward-traveling transmitted wave energy without changing
direction? Please don't just ignore that question.

Dr. Best dismissed the rearward-traveling energy and simply magically re-
introduced it into the forward wave. Do you also believe in magic? Dr. Best
also denied that interference had anything to do with matching when, in reality,
interference has everything to do with matching. A Z0-match point in a
feedline with reflections is impossible without interference.

Why didn't you object to Dr. Best's use of "bouncing waves"? Here's a quote
from his article: "When the system reaches the steady state, the two rearward-
traveling waves at the match point are 180 degrees out of phase with respect
to each other and a complete cancellation of both waves occurs."

That is a true statement and Melles-Griot and I have said exactly the same thing.
The question is: What happens to the energy in those cancelled waves? It doesn't
continue on toward the source. It doesn't stand still. It is not destroyed. Can
you guess what happens to it? Melles-Griot says it appears in the forward wave.
Do you think "appears" is a magic word? Can energy suddenly appear from nowhere?

Hecht in _Optics_ tells us that added constructive interference energy always
originates from and is equal in magnitude to the lost destructive interference
energy. Anything else violates the conservation of energy principle. The
answer is obvious. Destructive interference energy left over from the
cancellation of two rearward-traveling reflected waves changes direction
and appears in the forward wave. There is simply no where else for it to go.

I think I have finally figured out the root of the disagreement. Your
approach is similar to a one-trick pony. You have latched onto the
concept of interference to the exclusion of any other valid approach.

Nope, I'm open for any other valid approach but nobody has furnished another
one so far. I'm not interested in net answers. I'm interested in explaining
the physical process within the accepted laws of physics. No magic or steady
state short cuts accepted.
--
73, Cecil http://www.qsl.net/w5dxp



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Richard Clark wrote:

Gene Fuller wrote:
The Maxwell's equations approach does not require this
sort of crutch. Try it, you might like it.

It's not about being correct, it's about "truth" and proving the great
satan Steve wrong. When you've been flashed fried, facts don't
matter anymore. ;-)

Maxwell's equations yield answers but give no clue as to the
detailed physical process involved. Since everyone already
knows the answers, Maxwell's equations are no help at all
in explaining the 1, 2, 3, ... step-by-step process.

Here's a quote from Steve's article: "When the system reaches the
steady state, the two rearward-traveling waves at the match point
are 180 degrees out of phase with respect to each other and a complete
cancellation of both waves occurs."

I agree with that statement. But when I ask what happens to the energy
in those two cancelled waves, all I get is silence. So Richard, what
happens to the energy in those two cancelled waves? Destroyed? Bleeds
off to a parallel universe? Routed through a black hole for constructive
interference in the opposite direction? The answer is more than obvious.
Maxwell's equations tell us that all the energy in a Z0-matched system
winds up incident upon the load. That necessarily includes all the
energy in the rearward-traveling cancelled waves.
--
73, Cecil http://www.qsl.net/w5dxp



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On Thu, 11 Mar 2004 23:26:43 -0600, Cecil Moore
wrote:

Maxwell's equations yield answers but give no clue as to the
detailed physical process involved.

Clueless, hmm?

Since everyone already knows the answers,

All the answers and no clues, even more curious.

Maxwell's equations are no help at all
in explaining the 1, 2, 3, ... step-by-step process.

You got more problems than clues and answers.

Here's a quote from Steve's article

Ah, the great satan having been invoked. How'd I peg that so square
on the head?


I agree with that statement. But when I ask what happens to the energy
in those two cancelled waves, all I get is silence.

That's all it merits,

So Richard, what
happens to the energy in those two cancelled waves? Destroyed? Bleeds
off to a parallel universe? Routed through a black hole for constructive
interference in the opposite direction? The answer is more than obvious.

From those three alternatives drawn from a hat? Three card monte is a
more honest game. You forgot the part about truth, justice and the
american way....

Maxwell's equations tell us ...

And here you told us that maxwell's equations were clueless, answers
that described nothing and no help at all - unless they pass through
your model.

Well, I did say this was more entertaining than video on demand.
Lower bandwidth too.

73's
Richard Clark, KB7QHC

Regardless of impedances, with a sensibly zero-loss line it's quite obvious
ALL the power leaving the generator is dissipated in the load. There's
nowhere else for the stuff to go.

If any power is NOT dissipated in the load due to any cause then it never
leaves the generator.

What on earth have bouncing waves, virtual this that and the other got to do
with it.
----
Reg, G4FGQ