Revisiting the Power Explanation
 

Owen Duffy wrote:
Cecil Moore wrote in news:ZbBOh.19326$uo3.18213
@newssvr14.news.prodigy.net:

Remember, the magnitude of energy in a transmission line
is *EXACTLY* the amount of energy needed to support
the forward joules/sec and the reflected joules/sec.

If you go beyond your (unqualified) average view of the world and drilled
down on the fields in the line as a function of time and position, and
their relationship with steady state real and reactive energy flow at each
end of the line in the general case, it may provide you with a more correct
view of the tranmission line and its load and source in your favoured
energy context.

I have done that, Owen, and let's see if your experience is
different from mine. Please go to the following Florida State
University web page:

http://micro.magnet.fsu.edu/primer/j...ons/index.html

Leave the wavelength and amplitude the same. Change Wave A
to zero phase and change Wave B to a phase of 180 degrees.
The resultant superposed sum is zero obviously containing
zero energy.

What happened to the energy in Wave A and Wave B is
explained in the last paragraph. If Wave A and Wave B
occur in a transmission line, guess what happens to the
direction of the energy that cannot be destroyed?
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote:
Gene Fuller wrote:

Utter nonsense. Jim was pulling your chain, and I guess you fell for it.


Perhaps your argument is with Jim.

Disclaimer:
Ideas can tend to become severely distorted when projected through the
convolutions of Cecilspeak - for whatever reason.

I'm happy to discuss any comments that I have made. Less so about
comments that Cecil makes "on my behalf".

73 de ac6xg

Revisiting the Power Explanation
 

Hi Cecil -

We've been over this a hundred times already. The only way to get
past it is for you to try to understand that my comment and Eugene
Hecht's are both true. You need to find a way to understand that
there is no contradiction. You could start by noting that Hecht does
not contradict anything that I said. Nowhere does he claim that
interference redirects energy. That's your claim! And I haven't said
that energy isn't redirected. If redirection of energy takes place,
it takes place by reflection - not interference. It's just basic optics.

73, ac6xg




Cecil Moore wrote:

Jim Kelley wrote:

Moreover, destructive interference does not "redirect" or otherwise
cause anything to happen.


May I direct you to page 388 of "Optics" by Hecht
where he asserts that total destructive interference
must be matched by an equal magnitude of total
constructive interference. Since there are only two
possible directions in a transmission line, total
destructive interference in one direction must be
matched by an equal magnitude of total constructive
interference in the opposite direction. From my
energy analysis article, a reference:

http://micro.magnet.fsu.edu/primer/j...ons/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, ..."

This is a very tough question: In a transmission line with only
two directions reckon what "redistributed in a new direction"
would necessarily mean? :-)

Revisiting the Power Explanation
 

Keith Dysart wrote:
Once again the hypothetical equality
Preflected = Pdissipated + Pre-reflected
229.6 = 872 + 0
does not hold.

I have pointed out your errors and misconceptions
3-4 times and you have refused to correct them.
This is the last time I am going to waste my
time.

The source is a 2A Norton with a shunt 450 ohm
resistor. During steady-state, the source sees
75 ohms. Adding 1WL of 75 ohm lossless line doesn't
change anything but for the Nth time, points out
your errors and misconceptions.

source--1WL 75 ohm line--+--1000' 450 ohm line--75 ohm load
Pfor1-- Pfor2-- Pload
--Pref1 --Pref2

Taking your numbers, Pload = 220.4w, Pfor2 = 450w, and
Pref2 = 229.6w

Obviously Pfor1 = Pload = 220.4w and Pref1 = ZERO

The joules/sec into the impedance discontinuity must equal
the joules/sec out of the impedance discontinuity. Let's
see if they do.
Pfor1 + Pref2 = Pref1 + Pfor2
220.4 + 229.6 = ZERO + 450
450 joules/sec = 450 joules/sec

There you have it. You simply made a mistake. There is NO
violation of the conservation of energy principle. The
same conditions that exist at the impedance discontinuity
also exist at the source. Total destructive interference
toward the source is accompanied by total constructive
interference toward the load. Every sliver of energy is
accounted for. You analysis is, once again, simply wrong.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Jim Kelley wrote:
I'm happy to discuss any comments that I have made. Less so about
comments that Cecil makes "on my behalf".

When I described how you had talked me into changing
my mind about energy and power, here was Gene's response.

Utter nonsense. Jim was pulling your chain, and I guess you fell for it.

Gene is a physicist. So which one of you physicists
is right?
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Jim Kelley wrote:
We've been over this a hundred times already. The only way to get past
it is for you to try to understand that my comment and Eugene Hecht's
are both true. You need to find a way to understand that there is no
contradiction. You could start by noting that Hecht does not contradict
anything that I said. Nowhere does he claim that interference redirects
energy. That's your claim! And I haven't said that energy isn't
redirected. If redirection of energy takes place, it takes place by
reflection - not interference. It's just basic optics.

Please access the Florida State web page and set Wave A
to zero phase while setting Wave B to 180 degrees. Wave A
and Wave B continue to exist until they encounter each
other at which point their superposed amplitude goes to
zero indicating the the waves have been canceled. Since
energy cannot be canceled, where did the energy components
in the two waves go? Where it goes is explained at the
bottom of the web page. It is "redistributed", a synonym
for "redirected". In a transmission line, when the energy
is redistributed away from one direction, what other
direction can that redistribution take?

http://micro.magnet.fsu.edu/primer/j...ons/index.html

There is clearly total destructive interference between
Wave A and Wave B when they are of equal magnitudes and
opposite phases and energy redistribution necessarily
takes place.

In the past, you have said that redistribution of energy
from canceled waves is absolutely NOT a reflection yet
above you seem to say the redirection is a reflection.
Are you changing your mind about wave cancellation
resulting in reflections?
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

On Mar 28, 7:38 pm, Cecil Moore wrote:
Keith Dysart wrote:
Once again the hypothetical equality
Preflected = Pdissipated + Pre-reflected
229.6 = 872 + 0
does not hold.

I have pointed out your errors and misconceptions
3-4 times and you have refused to correct them.
This is the last time I am going to waste my
time.

Thank you for your patience. With just a bit more we
might actually get some where.

The source is a 2A Norton with a shunt 450 ohm
resistor. During steady-state, the source sees
75 ohms.

Both true.

Adding 1WL of 75 ohm lossless line doesn't
change anything

Unfortunately, far from true. Much changes. Of particular
interest here is that there are now ghosts in the
transmitted signal indicating the presence of re-reflected
reflected signals. These were not present in the original
experiment.

There you have it. You simply made a mistake.

I will not deny the possibility of mistakes. While proof
reading my example I found too many trivial arithmetic
errors to have complete confidence that none remain.
Still, you need to find the errors in my example, not
make changes to the example and then state there are
errors because the new example yields different results.

On the whole, I think progress is being made, though
painfully slowly. We have learned that adding a
wavelength of line does change things and this goes
against often quickly given conventional wisdom.

While the resulting steady state may be the same, the
transient response can be quite different. And, of
course, it is the transient behaviour that produces
ghosts.

To fully understand transmission lines, a student in
the field needs to spend some time thinking about and
understanding them in the time domain. Only by doing
this will a complete understanding of the behaviour
be possible.

In any case, we are back to the previous experiment for
which no one has yet found any errors in the analysis.
Until someone does, "Cecil's Hypothesis" does not hold.

....Keith

Revisiting the Power Explanation
 

Keith Dysart wrote:
Cecil Moore wrote:
Adding 1WL of 75 ohm lossless line doesn't
change anything

Unfortunately, far from true. Much changes. Of particular
interest here is that there are now ghosts in the
transmitted signal indicating the presence of re-reflected
reflected signals. These were not present in the original
experiment.

Yes, they were. That is your point of confusion. You
cannot just willy-nilly declare that the reflections
have disappeared in violation of the conservation
of energy principle. The two configurations are
identical except for the additional delays which
don't change anything during steady-state. The ghosts
are still there as they always were. Your alleged
absence of ghosts never existed and is a dream which
requires violation of the conservation of energy
principle. You are free to dream but please don't
present your dreams as scientific reality.

We have learned that adding a
wavelength of line does change things ...

No, we have NOT learned that. We have learned that
adding a wavelength of line does NOT change anything
during steady-state and shines the light your previous
errors and misconceptions. The conditions at the source
are exactly the same during steady-state with and without
the 1WL additional line. Anything else would violate
the principles of distributed network theory.

While the resulting steady state may be the same, the
transient response can be quite different.

Yes, the transient response is somewhat different
because of the extra 1WL delay, but the steady-
state conditions are identical.

In any case, we are back to the previous experiment for
which no one has yet found any errors in the analysis.

I have pointed out your errors 5 times now. You can
lead a horse to water ...

Ramo and Whinnery give strict warnings about assumptions
of conditions inside a Norton equivalent source. You
didn't heed their warnings and got caught by your
misconceptions.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

On Mar 28, 9:01 pm, Cecil Moore wrote:
Keith Dysart wrote:
Cecil Moore wrote:
Adding 1WL of 75 ohm lossless line doesn't
change anything

Unfortunately, far from true. Much changes. Of particular
interest here is that there are now ghosts in the
transmitted signal indicating the presence of re-reflected
reflected signals. These were not present in the original
experiment.

Yes, they were.

Can you demonstrate that without changing the configuration of
the experiment? Only then will your demonstration be convincing.

And just for greater certainty, I forgot to mention that the
reflection coefficient from the line to the generator is 0 in
my experiment (generator impedance is equal to the line
characteristic impedance) so using the reflection coefficient,
there are no reflections.

We have learned that adding a
wavelength of line does change things ...

No, we have NOT learned that. We have learned that
adding a wavelength of line does NOT change anything
during steady-state

True. But ghosts are a transient phenomenom, not a steady
state one, so things have changed, as I said.

and shines the light your previous
errors and misconceptions. The conditions at the source
are exactly the same during steady-state with and without
the 1WL additional line. Anything else would violate
the principles of distributed network theory.

While the resulting steady state may be the same, the
transient response can be quite different.

Yes, the transient response is somewhat different
because of the extra 1WL delay, but the steady-
state conditions are identical.

So as I said, things are not the same. And ghosts are a
transient phenomenom.

Please find errors without changing the experiment.

In any case, we are back to the previous experiment for
which no one has yet found any errors in the analysis.

I have pointed out your errors 5 times now. You can
lead a horse to water ...

May I suggest again that obtaining a different result with a
different experiment is not a surprise. If there are errors
in my example, you need to find them there, not in some
alternative experiment.

Ramo and Whinnery give strict warnings about assumptions
of conditions inside a Norton equivalent source. You
didn't heed their warnings and got caught by your
misconceptions.

You have misunderstood my generator. It is not a Norton
equivalent, so any warnings from Ramo and Whinnery do not
apply. Rather, it IS a generator with a current source and
a parallel resistor. That is the experiment. So the
computations of dissipations are valid for the experiment.

....Keith

Revisiting the Power Explanation
 

Keith Dysart wrote:
Can you demonstrate that without changing the configuration of
the experiment? Only then will your demonstration be convincing.

Anyone can demonstrate that by setting it up on the bench.
Guaranteed, you would see ghosting where you deny they exist.

And just for greater certainty, I forgot to mention that the
reflection coefficient from the line to the generator is 0 in
my experiment (generator impedance is equal to the line
characteristic impedance) so using the reflection coefficient,
there are no reflections.

Because it is an active source, not a passive resistor,
your reflection coefficient is wrong.

So as I said, things are not the same. And ghosts are a
transient phenomenom.

OTOH, because of noise, steady-state cannot exist
in reality so fixed ghosting is as close to steady-
state as we are going to get.

Please find errors without changing the experiment.

I did. Your simple-minded reflection coefficient is bogus.

May I suggest again that obtaining a different result with a
different experiment is not a surprise.

The two experiments are only different in your mind, not
in reality. The results of both experiments are the same
and you can prove it to yourself on the bench.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote:

Keith Dysart wrote:

And just for greater certainty, I forgot to mention that the
reflection coefficient from the line to the generator is 0 in
my experiment (generator impedance is equal to the line
characteristic impedance) so using the reflection coefficient,
there are no reflections.

Because it is an active source, not a passive resistor,
your reflection coefficient is wrong.

He will completely ignore this and keep insisting on his truth. Me
thinks he is trolling......

Revisiting the Power Explanation
 

Cecil Moore wrote in
et:

Owen Duffy wrote:
Cecil Moore wrote in news:ZbBOh.19326$uo3.18213
@newssvr14.news.prodigy.net:

Remember, the magnitude of energy in a transmission line
is *EXACTLY* the amount of energy needed to support
the forward joules/sec and the reflected joules/sec.

If you go beyond your (unqualified) average view of the world and
drilled down on the fields in the line as a function of time and
position, and their relationship with steady state real and reactive
energy flow at each end of the line in the general case, it may
provide you with a more correct view of the tranmission line and its
load and source in your favoured energy context.

I have done that, Owen, and let's see if your experience is
different from mine. Please go to the following Florida State
University web page:

http://micro.magnet.fsu.edu/primer/j...terference/wav
einteractions/index.html

Cecil, I am talking about the way in the steady state in which energy is
stored in E and H fields within the transmission line when standing waves
exist, and the way in which energy is exchanged between E and H fields
within the line, and the load and the source at each end of the line, and
the net energy flow averaged over time (power).

Your analysis of energy waves or power waves doesn't give you the
information to see that level of detail.

Owen

Revisiting the Power Explanation
 

On Mar 28, 10:20 pm, Cecil Moore wrote:
Keith Dysart wrote:
Can you demonstrate that without changing the configuration of
the experiment? Only then will your demonstration be convincing.

Anyone can demonstrate that by setting it up on the bench.
Guaranteed, you would see ghosting where you deny they exist.

So you find no flaws in my analysis but insist that the results
are incorrect. Hhhmmmmm.

And just for greater certainty, I forgot to mention that the
reflection coefficient from the line to the generator is 0 in
my experiment (generator impedance is equal to the line
characteristic impedance) so using the reflection coefficient,
there are no reflections.

Because it is an active source, not a passive resistor,
your reflection coefficient is wrong.

May I suggest that you check any reference on the subject of
reflection coefficient. In none of them will you find the
definition to have anything other than two impedances.

So as I said, things are not the same. And ghosts are a
transient phenomenom.

OTOH, because of noise, steady-state cannot exist
in reality so fixed ghosting is as close to steady-
state as we are going to get.

Sorry. No ghosts in my example.

For practical examples, you could consider any reference that
discusses driving digital signals down a transmission line.
One of the options for preventing reflections (which can
really mess up the reception of the signal), is matching
at the source. Others include matching at the load end.
The pros and cons of the various options will be discussed.

Please find errors without changing the experiment.

I did. Your simple-minded reflection coefficient is bogus.

Reflection coefficient is actually quite simple.

RC = (Z2-Z1)/(Z2+Z1)

I challenge you to find any reference with a different definition.

But to explore your contention that RC is different when there
is an active source, could you kindly provide the expression
describing RC in such a situation.

It occurs to me that you may not be aware how to compute the
impedance of circuit with active sources. Its quite simple.
Replace the voltage sources with shorts and the current sources
with opens. Then using the rules for parallel and series
impedances, compute the result. Use this in the expression
for RC.

May I suggest again that obtaining a different result with a
different experiment is not a surprise.

The two experiments are only different in your mind, not
in reality. The results of both experiments are the same
and you can prove it to yourself on the bench.

Well, then just use my experiment so that we do not have to
argue about whether they are the same.

When you compute the quantity of the re-reflection that
my experiment generates, I will be convinced. But do not
be surprised that I am not convinced when you compute the
reflections for a different experiment.

....Keith

Revisiting the Power Explanation
 

On Mar 28, 11:40 pm, Dan Bloomquist wrote:
Cecil Moore wrote:
Keith Dysart wrote:

And just for greater certainty, I forgot to mention that the
reflection coefficient from the line to the generator is 0 in
my experiment (generator impedance is equal to the line
characteristic impedance) so using the reflection coefficient,
there are no reflections.

Because it is an active source, not a passive resistor,
your reflection coefficient is wrong.

He will completely ignore this and keep insisting on his truth. Me
thinks he is trolling......

Good day Dan,

I offer you the same challenge as Cecil, find the error in my
analysis and then compute the correct amount of re-reflection.

And provide the expression for computing RC in the presence of
sources if it is different than the conventional
RC=(Z2-Z1)/(Z2+Z1).

When you find nothing wrong with the analysis, ask yourself why
you don't believe the results?

....Keith

Revisiting the Power Explanation
 

Dan Bloomquist wrote:
He will completely ignore this and keep insisting on his truth. Me
thinks he is trolling......

Please don't discourage innovation. He can patent his
ten cent method of eliminating reflections and obsolete
the circulator market. Maybe someone should warn
Tektronix.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Owen Duffy wrote:
Your analysis of energy waves or power waves doesn't give you the
information to see that level of detail.

Whatever level of detail one chooses, the energy
in the forward waves plus the energy in the reflected
waves will equal the total energy in the transmission
line which will always be the energy sourced and not
delivered to the load (in a lossless system). This
will be true right down to the last photon.

Unless someone can prove that EM energy is
transformed into some other form of energy for
storage in the transmission line and then transformed
back to EM energy when the transmission line is
emptied, the nature of EM energy and the conservation
of energy principle dictate what happens. EM (photonic)
wave energy cannot move at less than the speed of
light (modified by VF).
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

On Mar 29, 7:00 am, "Keith Dysart" wrote:
Good day Dan,

I offer you the same challenge as Cecil, find the error in my
analysis and then compute the correct amount of re-reflection.

Since it can be quite difficult to locate errors in analysises,
I'll offer a simpler challenge to you and Cecil.

For the example I proposed, using the approach of your choice,
compute the magnitude of the first re-reflected signal to reach
the load.

Recall the line is 31 wavelengths long so the signal reaches
the load 31 cycles after the generator is turned on. There is
a reflection which reaches the generator 31 cycles later and
any re-reflection will reach the load after a further 31 cycles.

So you need to compute the magnitude of the reflection which
reaches the load after 93 cycles. This would be the first ghost.

You need to show your work. Handwaving -25dB will not be considered
as answering the question.

....Keith

PS. If you prefer, you may use a slightly different example for
which computation may be easier:
- the line is 1 second long
- the generator creates a 450 V step function at time 0
What is the magnitude of the re-reflection that reaches the load
after 3 seconds?

PPS. The answer to the two problems will be the same.

Revisiting the Power Explanation
 

Keith Dysart wrote:
So you find no flaws in my analysis but insist that the results
are incorrect. Hhhmmmmm.

The flaws have been pointed out and you have ignored them.
THE REFLECTED WAVE DOES NOT SEE Rs=450 OHMS IF THE SOURCE
IS TURNED ON. THE REFLECTED WAVE DOES NOT EXIST IF THE
SOURCE IS TURNED OFF. Take a look at:

http://www.w2du.com/r3ch19a.pdf

Sorry. No ghosts in my example.

Correction: No ghosts in your wet dream. I suggest that you
patent your ten cent solution to eliminate reflections and
sell the patent to Tektronix since you have obviously rendered
all those expensive circulators in the world obsolete. And why
would anyone go to the trouble of installing a 20 dB pad when,
according to you, a single ten cent resistor will perform better?

Reflection coefficient is actually quite simple.
RC = (Z2-Z1)/(Z2+Z1)
I challenge you to find any reference with a different definition.

Sorry, all my references are at my new QTH but here are
a few from memory:

rho = SQRT(Pref/Pfor) = Vref/Vfor = Iref/Ifor = (SWR-1)/(SWR+1)

One of the options for preventing reflections (which can
really mess up the reception of the signal), is matching
at the source.

Yes of course, one can do that with a circulator or pad. One
cannot accomplish "matching at the source" with a ten cent
resistor. Such an assertion is sophomoric.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Keith Dysart wrote:
I offer you the same challenge as Cecil, find the error in my
analysis and then compute the correct amount of re-reflection.

We will be glad to do that if you will provide the
impedance value encountered by the reflected wave
with the source turned on. You have not yet done that.
Hint: It doesn't matter what impedance the reflected
wave encounters with the source turned off since
reflected waves are non-existent during that
condition.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Keith Dysart wrote:
So you need to compute the magnitude of the reflection which
reaches the load after 93 cycles. This would be the first ghost.

We cannot do that until you furnish more information about
the source. A math model would be nice.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

On Mar 29, 9:29 am, Cecil Moore wrote:
Keith Dysart wrote:
I offer you the same challenge as Cecil, find the error in my
analysis and then compute the correct amount of re-reflection.

We will be glad to do that if you will provide the
impedance value encountered by the reflected wave
with the source turned on. You have not yet done that.
Hint: It doesn't matter what impedance the reflected
wave encounters with the source turned off since
reflected waves are non-existent during that
condition.

The problem is completely solvable with the information
provided.

For examples of the methodology, google
'"lattice diagram" reflection'.

If your alternate methodologies require more information
to solve the problem, then I suggest that such alternate
methodologies are inferior to the standard one.

And to answer your question: 450 Ohms.
And to be more precise, the reflected wave continues for 62
cycles after the current source is turned off.

But truly, do look up lattice diagrams and learn the technique.
The number of problems that you will be able to solve will go
up significantly.

....Keith

Revisiting the Power Explanation
 

On Mar 29, 8:17 am, Cecil Moore wrote:
Dan Bloomquist wrote:
He will completely ignore this and keep insisting on his truth. Me
thinks he is trolling......

Please don't discourage innovation. He can patent his
ten cent method of eliminating reflections and obsolete
the circulator market. Maybe someone should warn
Tektronix.

I would hope that the patent application would be rejected
due to prior art, but given the current state of the patent
office, I am not sure how much confidence I would have.

I expect that Tek is well aware and that were you to examine
the output circuits of their signal generators, there is a
very high probability that you will be able to locate the
voltage source and the 50 Ohm resistor. I know I just found
them on a randomly selected Agilent signal generator.

....Keith

Revisiting the Power Explanation
 

On Mar 29, 9:08 am, Cecil Moore wrote:
Keith Dysart wrote:
Reflection coefficient is actually quite simple.
RC = (Z2-Z1)/(Z2+Z1)
I challenge you to find any reference with a different definition.

Sorry, all my references are at my new QTH but here are
a few from memory:

rho = SQRT(Pref/Pfor) = Vref/Vfor = Iref/Ifor = (SWR-1)/(SWR+1)

Yes, but these are less than useful aren't they. SQRT is
multi-valued so is never any use, and they all express
rho in terms of that which we want to derive rather than
in terms of that which we know. Means we need to know the
answer before we can compute the answer. Ooooopppps.

One of the options for preventing reflections (which can
really mess up the reception of the signal), is matching
at the source.

Yes of course, one can do that with a circulator or pad.

Or a single 10 cent resistor following the voltage or current
source. But I digress. Do look up "lattice diagram".

....Keith

Revisiting the Power Explanation
 

Cecil Moore wrote:

In the past, you have said that redistribution of energy
from canceled waves is absolutely NOT a reflection yet
above you seem to say the redirection is a reflection.
Are you changing your mind about wave cancellation
resulting in reflections?

Hi Cecil -

Please, I've asked you this many times, quote me directly when you
want to refer to something I've said. I am able to explain those
things. I concede that I am unable to explain the convoluted ideas
that you often attribute to me - although I do think I know why you
write them the way you do. For the sake of clarity and simplicity
could we instead try to restrict our dialog to the present discussion,
and include relevant text that is quoted from the post we wish to
comment upon? I think that's how it's customarily done in the newsgroups.

Nothing from the University of Florida contradicts what I said, and I
can find nothing there to object to. My comments were directed
strictly toward some of the things that you wrote. (As a courtesy I
included the text I was referring to). I would like to suggest that
you take more careful note of those areas where your words differ from
those contained in the papers that you cite; in particular, with
regard to interference as a *cause* for the redirection of energy. Do
not infer, as you then risk inferring incorrectly. If you're honest
about it, you will find that interference is the manifestation of a
redirection of energy. It is the form; the envelope of the
distribution. It is a result; the result of the superposition of
waves. Nowhere in the literature will you find anyone describing
interference as a cause of reflection, as you have done. That is
because it is not a factual accounting of the natural phenomena.

Thanks and 73,

Jim AC6XG

Revisiting the Power Explanation
 

Keith Dysart wrote:
But truly, do look up lattice diagrams and learn the technique.
The number of problems that you will be able to solve will go
up significantly.

Since your use of it yielded erroneous results, I think
I will pass. However, it appears to be much like the
S-Parameter analysis which does yield correct results.

An S-Parameter analysis indicates that you have made an
error in the reflection coefficient, s11, looking into
the 450 ohm transmission line. From HP's Ap-Note 95-1,
s11 is defined as the "Input reflection coefficient
with the output port TERMINATED BY A MATCHED LOAD."

You calculated your reflection coefficient with the
output port terminated by a mismatched load. There's
your conceptual error! The reflection coefficient, s11,
at the source is *NOT* the same as the reflection
coefficient at the load.

Have you told anyone else that an emitter follower with
a 450 ohm resistor in the emitter circuit will eliminate
reflections on all 450 ohm transmission lines?
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Keith Dysart wrote:
I expect that Tek is well aware and that were you to examine
the output circuits of their signal generators, there is a
very high probability that you will be able to locate the
voltage source and the 50 Ohm resistor. I know I just found
them on a randomly selected Agilent signal generator.

If they claim that the 50 ohm resistor eliminates reflections,
as you do, they could be sued for false advertising.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Keith Dysart wrote:
Or a single 10 cent resistor following the voltage or current
source. But I digress. Do look up "lattice diagram".

If your "lattice diagram" really tells you to use a
physical reflection coefficient looking one way and
a virtual reflection coefficient looking the other
way within the same analysis as you have done, it
is worthless.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote:

Jim Kelley wrote:

Walt doesn't actually indicate 'why' here, either. He is reciting a
set of well known circumstances, and implying that one set of facts
results in another. While the facts are obviously correct, any cause
and effect relationship between them must be inferred.


From his writings in "Reflections" and his postings
here, Walt obviously understands destructive and
constructive interference and the fact that (from
the Florida State University site):

"... All of the photon energy present in
these (cancelled) waves must somehow be recovered or
redistributed in a new direction, according to the
law of energy conservation ..."

In a transmission line we have two directions.
1. Toward the load
2. Toward the source

When the "photon energy" is "redistributed in a new
direction" in a transmission line, I'll bet it
goes in exactly the direction that Walt says it
goes.

If anyone in addition to Cecil thought that I was debating the facts
that Walt presented in Reflections, I apologize. I thought that I had
clearly stated that inferring a causal relationship between certain
sets of those facts had not been demonstrated therein.

73, ac6xg

Revisiting the Power Explanation
 

"Keith Dysart" wrote in message
ups.com...
On Mar 25, 8:23 pm, Cecil Moore wrote:

- The power into the 450 Ohm generator resistor is
38.6 Watts

Just to pick your nit, I think you meant 36.8 Watts. That would be closer to
the 36.7 Watts I obtained using a simplified approach.

Cheers,
John

Revisiting the Power Explanation
 

Cecil Moore wrote:

Here we are arguing semantics, not principles, again.

I was arguing principles, again. I don't bother with semantics (I
lack your expertise there). But I admit that I don't know why you
were arguing. ;-)

73, Jim AC6XG

Revisiting the Power Explanation
 

Jim Kelley wrote:
... in particular, with regard to interference
as a *cause* for the redirection of energy.

Here we are arguing semantics, not principles, again.
The total destructive interference that occurs during
wave cancellation leaves the associated energy with
no option except to be redistributed to an area of
constructive interference. Hecht says as much in
"Optics".
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Jim Kelley wrote:
If anyone in addition to Cecil thought that I was debating the facts
that Walt presented in Reflections, I apologize.

From "Reflections", by Walter Maxwell, 1st edition
Sec 4.3:

"The destructive interference causes mutual cancellation
of two complementary reflected waves ... Wave interference
between these two complementary waves ... causes a
cancellation of energy flow in the direction toward the
generator."

In the context that I am using the words, either
"superposition" or "interference" could be used. They
are two sides of the same coin.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote:

From "Reflections", by Walter Maxwell, 1st edition
Sec 4.3:

"The destructive interference causes mutual cancellation
of two complementary reflected waves ... Wave interference
between these two complementary waves ... causes a
cancellation of energy flow in the direction toward the
generator."

I don't know exactly what the dots represent above; presumably deleted
words. But perhaps it's best if you allow Walt to speak for himself,
lest you begin another "semantics" argument.

73, AC6XG

"Let's you and him fight." I like that. :-)

Revisiting the Power Explanation
 

Jim Kelley wrote:

Cecil Moore wrote:
Here we are arguing semantics, not principles, again.

I was arguing principles, again.

You have caused me to question the definition of a few
words. You have not caused me to question a single
technical principle. That's 100% pure semantics.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Jim Kelley wrote:
I don't know exactly what the dots represent above; presumably deleted
words.

Yes, it is common practice to delete words irrelevant
to the point being made.

But perhaps it's best if you allow Walt to speak for himself,

He did - in "Reflections", which I quoted.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

On Wed, 28 Mar 2007 16:26:10 -0700, Jim Kelley wrote:

Hi Cecil -

We've been over this a hundred times already. The only way to get
past it is for you to try to understand that my comment and Eugene
Hecht's are both true. You need to find a way to understand that
there is no contradiction. You could start by noting that Hecht does
not contradict anything that I said. Nowhere does he claim that
interference redirects energy. That's your claim! And I haven't said
that energy isn't redirected. If redirection of energy takes place,
it takes place by reflection - not interference. It's just basic optics.

73, ac6xg

Sorry Jim, but I take exception to your statement, "If redirection of energy takes place,
it takes place by reflection - not interference."

It is the interference between the forward and reflected voltages and beween the forward and reflected
currents that yields the resultant voltage and current values of rho at the matching point which produces
either a virtual short or a virtual open circuit that causes the re-reflection. I have shown this to be true
in my QEX article of Mar/Apr 1998, entitled, "Examining the Mechanics of Wave Interference in Impedance
Matching. It is also Chapter 23 in Reflections 2.

Using the complex values of rho I have shown the magnitude and phase relationships of the aforementioned
voltages and currents at the stub point that result in a virtual open circuit at the stub point to waves
reflected from a 3:1 mismatched load. The result is no reflections on the line between the stub and the
source, but a 3:1 SWR on the line between the mismatched load and the stub. If you don't have a copy of this
article please let me know and I'll send you one via email.

Walt, W2DU

Revisiting the Power Explanation
 

Cecil Moore wrote:
Jim Kelley wrote:
I don't know exactly what the dots represent above; presumably deleted
words.

Yes, it is common practice to delete words irrelevant
to the point being made.

But perhaps it's best if you allow Walt to speak for himself,

He did - in "Reflections", which I quoted.
--
73, Cecil, w5dxp.com

Does Walt have a point that he is trying to make here, Cecil?

73, ac6xg

Revisiting the Power Explanation
 

Jim Kelley wrote:
Does Walt have a point that he is trying to make here, Cecil?

Yes, but why don't you reply to his posting rather than mine?
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

On Mar 29, 1:38 pm, "John" wrote:
"Keith Dysart" wrote in message

ups.com...

On Mar 25, 8:23 pm, Cecil Moore wrote:
- The power into the 450 Ohm generator resistor is
38.6 Watts

Just to pick your nit, I think you meant 36.8 Watts. That would be closer to
the 36.7 Watts I obtained using a simplified approach.

Cheers,
John

Yes, indeed.

Thanks for checking.

....Keith

Revisiting the Power Explanation
 

On Mar 29, 12:35 pm, Cecil Moore wrote:
Keith Dysart wrote:
But truly, do look up lattice diagrams and learn the technique.
The number of problems that you will be able to solve will go
up significantly.

Since your use of it yielded erroneous results,

I am at a bit of a loss. You don't seem to have a methodology
to produce any results and yet you are sure mine are wrong.

I think
I will pass. However, it appears to be much like the
S-Parameter analysis which does yield correct results.

Feel free to apply any methodology of your choice to
predict the magnitude of the re-reflection. All information
about generator internals has been previously provided.

An S-Parameter analysis indicates that you have made an
error in the reflection coefficient, s11, looking into
the 450 ohm transmission line.

Have you computed the correct result then?

From HP's Ap-Note 95-1,
s11 is defined as the "Input reflection coefficient
with the output port TERMINATED BY A MATCHED LOAD."

You calculated your reflection coefficient with the
output port terminated by a mismatched load. There's
your conceptual error! The reflection coefficient, s11,
at the source is *NOT* the same as the reflection
coefficient at the load.

I am not sure where you are going with this. As you map
the system for s parameter evaluation, which is the two
port network that you are evaluating? The generator?
The load? The line?

Have you told anyone else that an emitter follower with
a 450 ohm resistor in the emitter circuit will eliminate
reflections on all 450 ohm transmission lines?

That is a leap that I wouldn't make. An ideal source, as
used in this example, must be able to both source and sink
current. You will need to specify more for us to determine
whether the circuit you propose will achieve that to a
sufficient degree.

....Keith