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