Jim Kelley wrote:
Cecil Moore wrote:
Does energy being redistributed in new directions really look
like a lack of interaction to you?

Roy is absolutely right, Cecil. Interact is a very poor choice of
terms in this discussion.

Roy did NOT say "interact" was a poor choice of terms. He
chose to use it as did Hecht. Hecht says waves interact.
Roy says they don't interact. I'm more likely to trust
Hecht over someone who says an S-Parameter analysis is
"gobbledigook" (sic) and doesn't even know how to
spell the word.

Would you assert that photons can have an
effect on each other?

Of course. Coherent photons emitted from different phased
antenna elements obviously have an effect on each other.
I suspect in addition to not understanding coherent
interference, you also don't understand coherency. When
coherent photons are traveling in the same path in the
same direction, they do not pass like ships in the night.
They affect each other. If they interfere destructively,
they redistribute some of their photonic energy in a
different direction. Every reference in the world says
that is what happens.

The fact is, waves and photons can only
interact with matter. If the superposition of waves actually had an
effect on the waves themselves then interference patterns wouldn't
look the way they do. Think about it.

I have thought long, hard, and deep about it. Wave cancellation
is prima facie evidence that coherent waves can have a permanent
effect on each other, even in free space. I don't know anything
more permanent than wave cancellation bringing both the net
E-field and the net H-field to zero.

No, not all coherent waves interfere. No, not all waves that
interfere cancel each other. Some of them do just the opposite.
But sometimes they do cancel. If you would wade through
the S-Parameter analysis with me, you would understand. An S-
parameter analysis of a Z0-match will expose the wave cancellation
toward the source for all to see. But it's rather obvious that
your mind is already made up, you think you know everything, and
will stop at nothing, including character assassination, to avoid
learning anything new.

How about taking the S-Parameter analysis step by step? Then
you can point out the very step where I wander astray of the
laws of physics.
--
73, Cecil http://www.w5dxp.com

Roy Lewallen wrote:
I've mentioned before that readers, like a group of triaged medical
patients, fall into three general categories:

1. Those who have made up their minds and won't have them changed no
matter what you say or what evidence you present;
2. Those who already agree with what you're saying;
3. Those who are willing to read what you say and can be convinced.

:-) As is usual for omniscient gurus, Roy doesn't even
comprehend that there is a number 4.

4. Those who question what you say and can prove that you are
wrong.

Is it possible for Roy to be wrong? How about using standing-
wave current with its unchanging phase to try to measure the
phase shift through a loading coil? Roy actually did exactly
that and, at last assertion, defends those ignorant
measurements. He still hasn't comprehended what he did wrong.

The day a guru forgets that 4th possibility above is the
day that he becomes an obsolete historical artifact. Two
waves redistribute their energy components in different
directions. How in the world is that not interaction?

Quotes from two web pages from the field of optical engineering:

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

"Clearly, if the wavelength of the incident light and the thickness
of the film are such that a phase difference exists between reflections
of p, then reflected wavefronts interfere destructively, and overall
reflected intensity is a minimum. If the two reflections are of equal
amplitude, then this amplitude (and hence intensity) minimum will be
zero." (Referring to 1/4 wavelength ideal thin films.)

"In the absence of absorption or scatter, the principle of conservation
of energy indicates all 'lost' reflected intensity will appear as
enhanced intensity in the transmitted beam. The sum of the reflected and
transmitted beam intensities is always equal to the incident intensity.
This important fact has been confirmed experimentally."

micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/waveinteractions/index.html

"... when two waves of equal amplitude and wavelength that are
180-degrees ... out of phase with each other meet, they are not actually
annihilated, ... All of the photon energy present in these waves must
somehow be recovered or *redistributed* in a new direction, according to
the law of energy conservation ... Instead, upon meeting, the photons
are *redistributed* to regions that permit constructive interference, so
the effect should be considered as a *redistribution* of light waves and
photon energy rather than the spontaneous construction or destruction of
light."

Here is a question for Roy: Lurkers with inquiring minds want to know:
How can a redistribution of energy in affected waves occur without
interaction between the waves? Magic? Divine intervention? What?
--
73, Cecil http://www.w5dxp.com

On 15 Apr 2007 14:33:40 -0700, "Jim Kelley" wrote:

On Apr 15, 6:53 am, Walter Maxwell wrote:
On Sun, 15 Apr 2007 19:23:56 +1000, Alan Peake
It is interesting to look at a single short pulse propagating along the
TL. At the stub point, the pulse must encounter a discontinuity in
impedance and therefore there will be a reflection. This can been seen
on a TDR. So there is a real reflection from a stub regardless of
whether or not it is a virtual short.
Alan
VK2ADB

I thank you for that, Alan, because, to continue, when the pulse is replaced with a sine wave, there is also a
reflection from the stub.

Hi Walt -

Begging your pardon, but don't TDR's examine the transient response of
a system, rather the steady state response?

ac6xg

You're correct, of course, Jim, but I was intuitively assuming we'd not be continuing the use of the TDR with
the sine wave signal. I'm sure my intuition wasn't communiated, sorry.

Walt

On Apr 15, 12:50 pm, Walter Maxwell wrote:

Seems to me that the only disagreement with my original posting is whether the condition at the stub point can
be called a 'virtual' short circuit.

Hi Walt,

Most everyone has directly expressed complete agreement with that
idea. Here's the recurring theme:


*******Virtual impedance discontinuities do not cause
reflections.********


73, Jim AC6XG

On Apr 15, 1:29 pm, Roy Lewallen wrote:
Jim Kelley wrote:
On Apr 15, 2:03 am, Roy Lewallen wrote:

After a number more frustrating and unresolved collisions with reality,
he wisely quit and got a teaching job. I'm sure he did well in the
academic world.

He doesn't sound like anyone I know that does "well" in the academic
world.

You were lucky. He closely resembled the majority of my college professors.

Roy Lewallen, W7EL

Hi Roy -

I didn't say that I don't know any like that, I just wouldn't say
they're doing 'well' at it. ;-)

ac6xg

On Sun, 15 Apr 2007 13:51:44 -0700, Roy Lewallen wrote:

I've mentioned before that readers, like a group of triaged medical
patients, fall into three general categories:

1. Those who have made up their minds and won't have them changed no
matter what you say or what evidence you present;
2. Those who already agree with what you're saying;
3. Those who are willing to read what you say and can be convinced.

Posting for the benefit of groups 1 and 2 is a waste of time, because
there's no difference in anyone's belief or knowledge from the beginning
to the end of the discussion. The third group, however, is worth while.
Unfortunately, the active posters often are composed of the first two
groups, and I see in this discussion that's been entirely the case. So
we're left to hope that the lurkers are taking something away from this.
To the lurkers out the I hope you've read the postings, looked at the
evidence, and reached some conclusions. Better yet, I hope some of you
have been spurred to learn more about the topic, do some investigation
of your own from reputable sources, and gain a deeper understanding of
the fundamentals involved.

I see that my statements that waves don't interact with or reflect from
each other in a linear medium is already being morphed into claims that
I've denied that superposition happens, even though I've been careful to
distinguish the two. So one final request to the lurkers: Read what I
wrote, not interpretations of what I wrote.

I've tried to explain my point in about every way I know how, and
further postings would just become more repetitive. So I'll bow out at
this point, disappointed because I've been totally ineffectual at
communicating my point to the active posters, but with hope that some of
the lurkers have understood. And Walt, I'm especially disappointed that
I've been unable to explain to you what I mean, because I fear that the
interpretive error will detract from and reduce the credibility of your
otherwise exceptional and wonderful works.

Roy Lewallen, W7EL

Hi Roy,

I thank you for the time and effort you've put in in expressing your position, but for all the attempts I've
made to appreciate your position, I'm now more confused than before the thread began. I don't know what else
to say other than it puts me squarely in the first of the three categories, doesn't it?

Walt

Walter, W2DU wrote:
"Thank you for the time and effort you`ve put in in expressing your
position-----."

Yes, Thank you very much and please add me to your catagory no. 3.

Best regards, Richard Harrison, KB5WZI

On 15 Apr 2007 15:10:11 -0700, "Jim Kelley" wrote:

On Apr 15, 12:50 pm, Walter Maxwell wrote:

Seems to me that the only disagreement with my original posting is whether the condition at the stub point can
be called a 'virtual' short circuit.

Hi Walt,

Most everyone has directly expressed complete agreement with that
idea.

Here's the recurring theme:


*******Virtual impedance discontinuities do not cause
reflections.********


73, Jim AC6XG

OK Jim, if that's so, then I've got to figure out a new way to explain how antenna radiation patterns are
modified by changing the relative phase of the signals fed to multiple radiators, and by changing the spacing
between the radiators. Looks like I've had it all wrong for lo these many years. I thought I've been reading
the same references as all the other posters.

Walt

On Apr 15, 2:39 pm, Cecil Moore wrote:
Jim Kelley wrote:
Cecil Moore wrote:
Does energy being redistributed in new directions really look
like a lack of interaction to you?

Roy is absolutely right, Cecil. Interact is a very poor choice of
terms in this discussion.

Roy did NOT say "interact" was a poor choice of terms.

That's correct. I said that interact is a poor choice of terms.

He
chose to use it as did Hecht. Hecht says waves interact.
Roy says they don't interact.

As I said, Roy is correct.

Would you assert that photons can have an
effect on each other?

Of course. Coherent photons emitted from different phased
antenna elements obviously have an effect on each other.

That is incorrect. Charged particles and photons interact in antennas.

I have thought long, hard, and deep about it. Wave cancellation
is prima facie evidence that coherent waves can have a permanent
effect on each other, even in free space. I don't know anything
more permanent than wave cancellation bringing both the net
E-field and the net H-field to zero.

And the funny thing is, you say that even you know of instances in
which the net fields are zero, and yet the waves propagate beyond that
point. You've at least seen a picture of an interference pattern,
right?

If you would wade through
the S-Parameter analysis with me, you would understand.

I think you just like to argue.

How about taking the S-Parameter analysis step by step? Then
you can point out the very step where I wander astray of the
laws of physics.

If the S parameter analysis addressed where you are going wrong, then
that might be worthwhile. The problem as I said is with your idea
about waves and energy. Obviously we all get the same answer at the
end of the problem.

73, Jim AC6XG

Richard Harrison wrote:
Yes, Thank you very much and please add me to your catagory no. 3.

And please add the 4th distinct possibility, that any mortal
human being can be proved to be wrong about something. :-)
--
73, Cecil http://www.w5dxp.com