Jim Kelley wrote:
BTW, not all forms of resistive loss are "ohmic".

The SQRT(L/C) of a lossless transmission line is certainly "ohmic".
Or are you willing to assert that the Z0 of coax is really j50 or
some such. May I suggest a good book on dimensional analysis?
--
73, Cecil http://www.qsl.net/w5dxp



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Jim, AC6XG wrote:
"Ummm, isn`t that an example of reactance?"

Terman on page 88 of his 1955 edition says:
"The characteristic impedance Zo is the ratio of voltage to current in
an individual wave---; it is also the impedance of a line that is
infinitely long or the impedance of a finite length of line when ZL =
Zo. It will be noted that at radio frequencies the characteristic
impedance is a resistance that is independent of frequency."

Isn`t that succinct and beautiful? Wish my thoughts were as clear and
true. We lost a treasure when he passed away.

Best regards, Richard Harrison, KB5WZI

Cecil Moore wrote:

Jim Kelley wrote:
Nowhere other than in Cecil's
works will one find a description of waves reversing direction without
reflecting from a discontinuity.

You have made that assertion so many times it has turned into a Big Lie.
Maybe you should reveal the agenda responsible for such unethical behavoir?

I guess you better reaveal it, because I have no idea what you're trying
to accuse me of.

The *energy* in the cancelled (destroyed) reflected waves reverses directions
at the Z0-match.

You just accused me of lying about your belief in that notion.

73, Jim AC6XG

Cecil Moore wrote:

Jim Kelley wrote:
BTW, not all forms of resistive loss are "ohmic".

The SQRT(L/C) of a lossless transmission line is certainly "ohmic".

You don't seem to know what the term "ohmic" means.

73, Jim AC6XG

Richard Harrison wrote:

Jim, AC6XG wrote:
"Ummm, isn`t that an example of reactance?"

Terman on page 88 of his 1955 edition says:
"The characteristic impedance Zo is the ratio of voltage to current in
an individual wave---; it is also the impedance of a line that is
infinitely long or the impedance of a finite length of line when ZL =
Zo. It will be noted that at radio frequencies the characteristic
impedance is a resistance that is independent of frequency."

Isn`t that succinct and beautiful? Wish my thoughts were as clear and
true. We lost a treasure when he passed away.

Absolutely. If only it were as relevant as it is succinct and
beautiful. But, that's a little out of Terman's hands at this point.
;-)

73, Jim AC6XG

Jim Kelley wrote:
Cecil Moore wrote:
The *energy* in the cancelled (destroyed) reflected waves reverses directions
at the Z0-match.

You just accused me of lying about your belief in that notion.

If you don't understand the difference between saying that cancelled
waves reverse direction and saying that the energy in the cancelled
waves reverses direction, you are beyond help.
--
73, Cecil http://www.qsl.net/w5dxp



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Jim Kelley wrote:

Cecil Moore wrote:
The SQRT(L/C) of a lossless transmission line is certainly "ohmic".

You don't seem to know what the term "ohmic" means.

From the IEEE dictionary: "ohmic contact ... one that has a linear
voltage/current characteristic throughout its entire operating range."
That certainly seems to describe the characteristic impedance of a
transmission line which has a linear voltage/current characteristic
throughout its entire specified operating range even though that Z0
is non-dissipative.

I'm assuming anything with the dimensions of "ohms" is "ohmic" but
I could be wrong. Do you have a reference otherwise?
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil,

Who said anything about distinguishing net waves or component waves? I
was talking about a complete solution.

If you read what I wrote you will note that I said any purported waves
traveling in the reverse direction have zero amplitude. In other words
they do not exist.

If you choose to create any number of fictitious components that all
cancel, go right ahead. No professional does it that way.

You appear to misunderstand that it is essentially impossible to do
anything with all of your interfering component waves except wave your
hands and flap your gums about them. If you really want to get
quantitative answers then it is conventional to use ordinary
electromagnetic theory starting with Maxwell's equations. No fictitious
canceling component waves are needed as input, nor do they arise as
output from a correct analytical treatment.

Really, this is standard textbook stuff. If you would like exact
references by title and page I will be happy to provide them.


73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

I don't have to "prove" anything. Just set up the standard wave
equations with the standard boundary conditions and the problem
practically solves itself. The non-zero remaining waves are all moving
in the same direction. I forgot to ask them if they realize that Cecil
doesn't approve of such behavior.


You should have warned us that you were talking about NET waves and
NET energy transfer. I'm not discussing that at all. I am talking about
component waves and component energy transfer without which standing
waves cannot exist. Or maybe you can offer an example of standing waves
in the absence of at least two waves traveling in opposite directions.
If you can do that, I will admit defeat.

I suppose this is an prime example of being seduced by "math models",
but I believe that is a lesser fault than being seduced by Cecil's
imaginary models.


It is indeed an example of being seduced by the NET math model. Please
transfer over to the component math model and rejoin the discussion.
Lots of interesting things are happening below the threshold of the
NET math model. The NET math model doesn't explain anything except
the NET results. If your bank account balance doesn't change from one
month to another, do you also assume that you have written no checks
and have no income for that month? Literally speaking, please get real!

Gene Fuller wrote:
If you read what I wrote you will note that I said any purported waves
traveling in the reverse direction have zero amplitude. In other words
they do not exist.

So you disagree with "Wave Mechanics of Transmission Lines, Part 3:"
by S. R. Best, QEX Nov/Dec 2001?

Your statement denies reality. In the following system, 178 joules/sec
are rejected by the load and thus flow back toward the source. You can
measure it with a wattmeter. The very first thing you need to prove is
that standing waves can exist without two waves flowing in opposite
directions. Anything short of that proof is just handwaving and gum
flapping on your part.

278W forward--
100W XMTR---50 ohm feedline---x---1/2WL 450 ohm feedline---50 ohm load
--178W reflected

You appear to misunderstand that it is essentially impossible to do
anything with all of your interfering component waves except wave your
hands and flap your gums about them.

If that is beyond your comprehension, just say so but, in reality, those
interfering component waves obey the laws of physics as explained in _Optics_,
by Hecht and on the Melles-Groit web page:

http://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.

In the absence of absorption or scatter, the principle of CONSERVATION OF
ENERGY indicates all "lost" reflected intensity will appear as ENHANCED
INTENSITY [constructive interference] in the transmitted beam."

That's pretty clear - 100% destructive interference between the two rearward-
traveling reflected wave components - 100% of the energy involved in the destructive
interference is not lost and joins the forward-traveling wave since it has no
other possible direction.

FYI, the equations governing the irradiance involving a perfect non-glare
thin film a Ir1+Ir2-2*SQRT(Ir1*Ir2) = reflected irradiance = 0 and
If1+If2+2*SQRT(If1*If2) = total forward irradiance Page 388 of _Optics_.
--
73, Cecil http://www.qsl.net/w5dxp



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On Tue, 9 Mar 2004 18:34:43 -0600, "Steve Nosko"
wrote:

or is this a troll, Cecil


Hi Steve,

Well - waddaya think?

No. No. The question answers itself in proportion to the chuckles.
Better than video on demand, and cheaper.

73's
Richard Clark, KB7QHC