Cecil Moore wrote:
I think Roger is talking about the phase shift at a reflection
point. If ZL Z0, the current reverses phase, i.e.
It = |If| - |Ir| = 0. If ZL Z0, the voltage reverses phase,
i.e. Vt = |Vf| - |Vf| = 0

Left out a few words - should be:

It = |If| - |Ir| = 0 at an open-circuit.

Vt = |Vf| - |Vr| = 0 at a short-circuit.
--
73, Cecil http://www.w5dxp.com

Roy Lewallen wrote:
Michael Coslo wrote:
Roy Lewallen wrote:


My postulate is that Newton was wrong: moving objects come to a rest
without any external applied force. Every observation made supports
this. There's no need to consider what happens in a frictionless
environment, since such a thing doesn't exist.


Isn't that like lossless wires, perfect grounds, and other such?

The conditions that cause an object to slow and stop in real life
are the proof of the law. To the contrary, it proves Newton correct.
The forces act just as they should.

- 73 de Mike N3LI -

To repeat my posting of Dec. 8:

--------------

This would be funny if it weren't sad. This newsgroup is one of the few
places I can think of where the silly statement I posted about moving
bodies and friction would be taken seriously. But it's really no
surprise, since it's much less unreasonable than the imaginative
alternative theories which are seriously presented, and just as
seriously argued, here daily.

My postulate about objects in motion was a parody of Cecil's rejection
of theoretical cases on the basis that they can't exist in practice, my
intent being to show how such a rejection leads to incorrect results.
But I see it's drawing the same serious response as Cecil's and Art's
postings. All that's missing is one of Richard's quotes from Terman and
support from Derek.


Okay, I get it now. I came in late on this one and was reading it
literally.

- 73 de Mike N3LI -

Cecil Moore wrote:

Actually, I believe that every disagreement between
Jim Kelley and myself has been semantic in nature.
There are no technical fundamentals upon which we
disagree.

I don't care about your use of words, Cecil. I am only concerned with
some of the concepts that you describe.

73, Jim AC6XG

Jim Kelley wrote:
Cecil Moore wrote:

Actually, I believe that every disagreement between
Jim Kelley and myself has been semantic in nature.
There are no technical fundamentals upon which we
disagree.

I don't care about your use of words, Cecil. I am only concerned with
some of the concepts that you describe.

I use words to describe those concepts. You and I do not
agree on the definitions of those words. Reality is what
it is. It is the different definitions that we are using
that is the problem.

For instance, what if I am using a different definition
than you are for "concepts" in your posting above? What
if you were writing in a language that I didn't understand?
The outcome would be similar to what we have now.
--
73, Cecil http://www.w5dxp.com

Jim Kelley wrote:
I am only concerned with
some of the concepts that you describe.

When you repeat those concepts back to me, they bear
no resemblance to the concepts that I am trying to
describe. That is proof that our disagreements are
semantic. (The only other possibility is that you
are unethical and are deliberately bearing false
witness against me.)

I use words to describe my concepts. You and I do not
agree on the definitions of those words. Reality is what
it is. It is the different definitions that we are using
that is the problem. "Transfer" is obviously one of those
words. I say all EM waves transfer energy. You say not
all EM waves transfer energy. It is simply that we are
using different definitions of the word "transfer".
There are many other words for which we have different
definitions.

You and I might as well be trying to communicate in two
foreign languages that neither one of us understand.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

Jim Kelley wrote:

I am only concerned with some of the concepts that you describe.


When you repeat those concepts back to me, they bear
no resemblance to the concepts that I am trying to
describe.

To you, they may not. But those concepts remain just as ludicrous no
matter who describes them. :-)

That is proof that our disagreements are
semantic. (The only other possibility is that you
are unethical and are deliberately bearing false
witness against me.)

The obvious possibility being dismissed out of hand is the one where
you are wrong and someone else is right.

I use words to describe my concepts. You and I do not
agree on the definitions of those words.

Yes. Others also use words, and there are cases where your
understanding of the meaning of the words is not necessarily the same
as the meaning intended by the author. We know this by comparing the
things you say about physics with fundamental principles of physics.

It is simply that we are
using different definitions of the word "transfer".

If that is the case then I am using the definition pertinent to the
physics of our discussion, and you are using whichever one you think
will prevent your argument from containing a false statement.

You and I might as well be trying to communicate in two
foreign languages that neither one of us understand.

But only if it suits the purposes of internet one-upsmanship,
apparently.

73, ac6xg

On Dec 12, 6:03 pm, Cecil Moore wrote:
Jim Kelley wrote:
I am only concerned with
some of the concepts that you describe.

When you repeat those concepts back to me, they bear
no resemblance to the concepts that I am trying to
describe. That is proof that our disagreements are
semantic. (The only other possibility is that you
are unethical and are deliberately bearing false
witness against me.)

I use words to describe my concepts. You and I do not
agree on the definitions of those words. Reality is what
it is. It is the different definitions that we are using
that is the problem. "Transfer" is obviously one of those
words. I say all EM waves transfer energy. You say not
all EM waves transfer energy. It is simply that we are
using different definitions of the word "transfer".
There are many other words for which we have different
definitions.

Can you expand on the two different interpretations of
"transfer" that will bring these views into alignment?

Perhaps you really are disagreeing on whether EM
waves always transfer energy (using the common
definition of "transfer").

....Keith

Jim Kelley wrote:
The obvious possibility being dismissed out of hand is the one where you
are wrong and someone else is right.

No, that is not dismissed out of hand. I enjoy being wrong
because I always learn something new. You have not proved
me wrong because you haven't even understood what I said.

When you repeat what you think I said, and it is
not what I said, there is something wrong besides
someone being technically incorrect and someone being
technically correct.
--
73, Cecil http://www.w5dxp.com

Keith Dysart wrote:
Can you expand on the two different interpretations of
"transfer" that will bring these views into alignment?

Perhaps you really are disagreeing on whether EM
waves always transfer energy (using the common
definition of "transfer").

Jim refuses to provide a reference for his definition
of "transfer". My unabridged Webster's has 20 definitions
for the word including, "to be moved from one place to
another". I say the light waves from Alpha Centauri are
transferring, i.e. moving energy from that star to other
points in the universe. The Poynting vector for those
light waves can be computed if necessary. EM waves cannot
exist without energy.
--
73, Cecil http://www.w5dxp.com

Keith Dysart wrote:
clip text...........


After considerable thought, I think the math you presented above is for one of two cases of reflective waves, the reflection from a higher impedance load. When the load is less than the Zo of the line, the currents add but voltages subtract. Right?



I don't think so. Vt = Vf + Vr, It = If - Ir, Vf = If * Z0 and Vr = Ir * Z0 are the fundamental equations defining forward and reverse waves. Perhaps you arrive at two choices because sometimes Vr and Ir are negative, which after simplification appears to give an alternate form?



The end result is the same for both cases.



This is good. If you chase the signs, though, I think you will find that there is only one case. We probably should not toss Power into the mix until agreement is reached on this. Power is fraught with issues which seriously confuse some. ....Keith

I can see that I need to further explain. 

My analysis always begins with the source because the first formation of the wave comes from the source, then travels through the transmission line system.  The source defines the wave only until the wave reaches any discontinuity(s) or the line end.   Thereafter, discontinuities and end conditions define the system,.

Why might I say that?   Initiation of the wave at the source results in a sine wave with the impedance of the transmission line, and the power and frequency of the  source.   This is a steady state condition until the first discontinuity or reflection point is reached by the traveling wave.   Each successive reflection point (discontinuity) reflects power which travels back to the source and changes the feed point impedance conditions.   The most distant possible reflection point is the end of the transmission line (ignoring reflections which might occur on the antenna) and might be an open circuit, a reactive resistance, or a short circuit.   Any power reflected from the end will change the measured impedance found at any point on the transmission line all the way back to the source, and will define the steady state conditions of the system.

If we accept that the steady state conditions are defined by the load, then we should examine the conditions on the source side of the load, assuming it is the end of the transmission line.  The forward wave spawns the reflective wave in one of two ways, one way of  load resistance higher than line impedance, and a second way of  load resistance lower than line impedance.   In both cases the power of both forward and reflective wave add, but the voltages and currents both add and subtract.   (Cecil explained it very well in his follow up postings.   Thanks Cecil.)  I presented the power equations to illustrate the two conditions.

It is convenient that both cases result in the same math for the directional watt meter.  

73, Roger, W7WKB