The folks on this newsgroup who argue that the concept
of reflected energy is invalid and only standing waves
exist seem forced to abandon the principle of
superposition which states that a system can be
analyzed by considering the components separately
and adding them later.

So does the Superposition Principle give us permission
to analyze the forward wave and the reflected wave
separately, or not?

An S-Parameter analysis obviously considers the
forward wave and reflected wave separately. Is such
an analysis invalid or simply honoring the rules set
forth in the Principle of Superposition?
--
73, Cecil http://www.w5dxp.com

The only dispute about superposition that I have observed is
that it does not apply to the computation of power which can
easily be demonstrated by the most trivial of examples.

Superposition of voltages and currents seems to be quite
accepted and is an excellent tool for circuit and transmission
line analysis.

....Keith

Keith Dysart wrote:
Superposition of voltages and currents seems to be quite
accepted and is an excellent tool for circuit and transmission
line analysis.

Do you really expect us to believe that those voltages
and currents can exist without energy? Maybe an example
of EM voltage and EM current existing without ExB joules/sec
would help.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Keith Dysart wrote:
Superposition of voltages and currents seems to be quite
accepted and is an excellent tool for circuit and transmission
line analysis.

Do you really expect us to believe that those voltages
and currents can exist without energy? Maybe an example
of EM voltage and EM current existing without ExB joules/sec
would help.

Cecil,

If you actually understood the way the Poynting Theorem works, you would
not waste your time worrying about ExB. It provides no useful
information in support of your wacky energy flow ideas.


Hint: Although the Poynting vector is defined as ExB, this is only a
flux. If you are interested in information relating to conservation of
energy it is necessary to integrate over a closed volume. The total
integral of the flux over the surface of that volume is then equal to
the rate of change of energy within the volume.

In your favorite example, where energy is coursing back and forth along
the two directions of a lossless transmission line, this integral over
any volume you choose will be exactly zero. Even if you could separate
the forward and reverse waves the Poynting vector energy calculation
would still come out to exactly zero for each component as well as the
sum of the components. The same amount of energy exits the integration
volume as enters it. Only in the case where there is a source or where
there is loss will the Poynting energy calculation yield a non-zero value.

If you want further information you can check advanced textbooks such as
"Classical Electrodynamics" by Jackson or "Principles of Optics" by Born
and Wolf. I am sure there are many other references, but those are the
two I check almost daily.

73,
Gene
W4SZ

Gene Fuller wrote:
Even if you could separate
the forward and reverse waves the Poynting vector energy calculation
would still come out to exactly zero for each component as well as the
sum of the components.

Forward and reflected waves are easily separated by a
circulator so their existence is difficult to deny.

So net energy equals zero? So what! We are NOT discussing net
energy here. We are discussing the forward Poynting vector
and the reflected Poynting vector as described in "Fields and
Waves ...", by Ramo and Whinnery. The Superpositon Principle
gives us permission to do so and the final result is identical
to any other valid analysis. Why are you guys so irrationally
afraid of the wave reflection model? What is your ulterior
motive in denying the existence of reflected waves during
steady-state? It has seemingly turned into a steady-state
religion administered by the steady-state high priests.
--
73, Cecil http://www.w5dxp.com

On Mar 30, 8:54 pm, Cecil Moore wrote:
Gene Fuller wrote:
Even if you could separate
the forward and reverse waves the Poynting vector energy calculation
would still come out to exactly zero for each component as well as the
sum of the components.

Forward and reflected waves are easily separated by a
circulator so their existence is difficult to deny.

You always seem to like changing the experiment and then not
acting surprised when you get different results.

Odd is it not?

....Keith

Cecil Moore wrote:
Gene Fuller wrote:
Even if you could separate the forward and reverse waves the Poynting
vector energy calculation would still come out to exactly zero for
each component as well as the sum of the components.

Forward and reflected waves are easily separated by a
circulator so their existence is difficult to deny.

So net energy equals zero? So what! We are NOT discussing net
energy here. We are discussing the forward Poynting vector
and the reflected Poynting vector as described in "Fields and
Waves ...", by Ramo and Whinnery. The Superpositon Principle
gives us permission to do so and the final result is identical
to any other valid analysis. Why are you guys so irrationally
afraid of the wave reflection model? What is your ulterior
motive in denying the existence of reflected waves during
steady-state? It has seemingly turned into a steady-state
religion administered by the steady-state high priests.


Cecil,

I guess I was not quite clear. I don't care if you are talking net
energy, gross energy, with or without circulators, or anything else. As
long as there are no sources or sinks of energy in the region of
interest, the Poynting vector tells you absolutely nothing about energy
balance or conservation of energy.

You could have a completely incorrect analysis of forward and reverse
waves, and the Poynting analysis will not reveal the error. The required
integral will still come out to exactly zero.

Radio amateurs and radio charlatans love to talk about Poynting vectors,
but it is obvious that most of those folks simply don't understand the
full picture. Just forget about ExB (or more commonly, ExH). It is
completely useless in support for the typical RRAA discussions.

73,
Gene
W4SZ

"Cecil Moore" wrote in message
...
Keith Dysart wrote:
Superposition of voltages and currents seems to be quite
accepted and is an excellent tool for circuit and transmission
line analysis.

Do you really expect us to believe that those voltages
and currents can exist without energy? Maybe an example
of EM voltage and EM current existing without ExB joules/sec
would help.
--
and yet again you cross up terms... voltage and current are on wires. E and
B are fields between or outside of wires. while they can be handled
similarly they should not be compared directly as you are asking. and yes,
there is at least one very good example of a voltage without ExB... just
charge a balloon up with some stray electrons and leave it alone long enough
to reach steady state... voila, E with no B. Please do this experiment and
reply when you have truly reached steady state.

"Dave" wrote ...

"Cecil Moore" wrote

Keith Dysart wrote:
Superposition of voltages and currents seems to be quite
accepted and is an excellent tool for circuit and transmission
line analysis.

Do you really expect us to believe that those voltages
and currents can exist without energy? Maybe an example
of EM voltage and EM current existing without ExB joules/sec
would help.
--
and yet again you cross up terms... voltage and current are on wires. E
and B are fields between or outside of wires. while they can be handled
similarly they should not be compared directly as you are asking. and
yes, there is at least one very good example of a voltage without ExB...
just charge a balloon up with some stray electrons and leave it alone long
enough to reach steady state... voila, E with no B. Please do this
experiment and reply when you have truly reached steady state.
I've been waiting for someone to open the door so that Art could take
part in this thread.Dave, your use of the balloon as an example will do the
job nicely. Art will now be able to contribute quite a lot, although I'm not
sure that he ever reaches steady state!

Mike W5CHR

On Mar 30, 12:44 pm, Cecil Moore wrote:
The folks on this newsgroup who argue that the concept
of reflected energy is invalid and only standing waves
exist seem forced to abandon the principle of
superposition which states that a system can be
analyzed by considering the components separately
and adding them later.

So does the Superposition Principle give us permission
to analyze the forward wave and the reflected wave
separately, or not?

An S-Parameter analysis obviously considers the
forward wave and reflected wave separately. Is such
an analysis invalid or simply honoring the rules set
forth in the Principle of Superposition?
--
73, Cecil http://www.w5dxp.com


We have done extensive research here at Muppet Labs, and we can assure
you, the Superstition Principle is alive and well, especially with
regard to radio amateurs' analyses of transmission lines.

From the Labs,
Dr. Honeydew