Walt, W2DU wrote:
"This ratio (reflection coefficient) is determined only by the load and
the line, not by the generator.."

Terman is squarely in Walt`s corner. He says on page 87 of his 1955
edition:
"Reflection coefficient = rho = E2 / E1
= (ZL/Zo) -1 / (ZL/Zo) +1.

No Zsource appears in the equation, only ZL and Zo. " Were it not so,
Terman would have told you!

There is a nice photo of Walt, W2DU in the April 1973 edition of QST.
That`s the edition with (2) Bird wattmeters on the cover. This edition
initiated a series of articles on "Reflections" by Walt.

Best regards, Richard Harrison, KB5WZI

"Walter Maxwell" wrote in message
...

This concept is foreign to me, so if I'm wrong I'd like to have some proof
that
the source impedance can have any influence on SWR.

Walt

Walt,

I don't think the source impedance has any effect on SWR. In fact I have
changed the source impedance and saw no change in SWR. But Since tha SWR
meter is a really dumb bunny, I wonder of the meter can be mislead by a
reactive source impedance that forces the current to be out of phase with
the voltage. Perhaps a case where the source and load both are reactive?

Tam/WB2TT

On Mon, 6 Oct 2003 12:51:09 -0500 (CDT),
(Richard Harrison) wrote:
No Zsource appears in the equation, only ZL and Zo. " Were it not so,
Terman would have told you!

Hi Richard,

Terman offers some expansion on your observation in his first footnote
to "Chapter 4 Transmission Lines"
"This material on transmission lines is a review and summary
of those concepts and relations that are most widely held in
radio work. It presupposes at least a little previous familiarity
with the subject, and therefore should not be regarded as a
self supporting presentation of transmission line theory."

Terman loves me this I know!
For "Electronic and Radio Engineering" tells me so.

:-)

73's
Richard Clark, KB7QHC

Tam, WB2TT wrote:
"--I wonder if the meter can be mislead by a reactive source impedance
that forces the current to be out of phase with the voltage."

In the usual h-f transmission line, Zo appears as an Ro. This means that
you put volts across it and the resulting current in the line travels
according to Ohm`s law controlled by the surge impedance of the line. Ro
means the current is in-phase with the volts across the line in both
directions of travel. The funny stuff seen on a line with reflections
comes from looking at both directions of travel at the same time. That`s
not the best way to look at the line and that`s why the Bird wattmeter
uses a directional coupler to extract information on the traveling wave
in one direction at a time.

Surely maximum power transfer is enabled by a conjugate match. "Dumb
bunny " SWR meters may indicate anything.

Terman says on page 76 of his 1955 edition regarding maximum power
transfer:
"This is accomplished by making the load the conjugate of its generator
impedance as defined by thevenin`s theorem."

It is Walt who is "bullet-proof" on this.

Best regards, Richard Harrison, KB5WZI

Richard Clark wrote:

everything can be explained by achieving a conjugate match ...

and I see nothing about that in a halfwave line that instead achieves
a Zo match, not a conjugate. A conjugate has very specific properties
and you cannot provide an expression that offers the conjugate for the
situation:

You conveniently trimmed off the rest of my statement. When the line
is lossy, it is possible to achieve a conjugate match at a point but nowhere
else. The requirement of a conjugate match for a lossy line is that the
impedance looking in either direction is the conjugate of the other direction.
That can be achieved at a single point in a lossy system, e.g. at the load.
The rule that if a conjugate match exists at one point, then a conjugate match
exists at all points, is *ONLY* true for lossless systems.

Let's just juggle the notion of Zo matching out with a slight boundary
change:

source=200 Ohm(resistive)---50 ohm feedline---load=600 Ohm(resistive)

What is the expression you offer to support your statement that yields
the conjugate? Barring an answer, it follows your statement that

everything can be explained by achieving a conjugate match ...

Again, please note that you deliberately snipped the context of that
statement, not a very ethical thing to do.

is yet another in a long list of absurdities.

Well, since you changed the contextual conditions away from a possible
conjugate match, nothing in the new example cannot be explained by
achieving a conjugate match, since a conjugate match is impossible in
the new example. What do you think changing the context proves? Nothing
that you have said is true at the center of the sun. How's that for a
context change?
--
73, Cecil http://www.qsl.net/w5dxp



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Richard Clark wrote:
My data stands un-refuted (barring the usual cackle of nay-saying
sneer review), and even more, without test at ANY other bench. I can
only conclude that:
1.) My data is bullet-proof;
2.) others lack the ability to perform the task;
3.) 1&2 above, but narcissistic debate is the real focus of critics.

I offered an experiment that might prove you right, Richard, but so
far you, nor anyone else, has offered any response.

Source---coax---(+j500)---SWR meter---(-j500)---50 ohm load

Seems to me the resonant reactances, in series or parallel, on each side
of the SWR meter, might add an equal magnitude of energy to the forward
energy and reflected energy seen by the SWR meter thus changing the SWR
reading. I suspect the above condition is representative of what you are
seeing in your measurements.
--
73, Cecil http://www.qsl.net/w5dxp



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Richard Harrison wrote:
In the usual h-f transmission line, Zo appears as an Ro.

RG-174 has about 6dB loss per 100ft on 12m. Its Z0 is equal
to Sqrt[(R+jXL)/(G+jXC)].

Does (R+jXL)/(G+jXC) really equal 2500 for RG-174 on 12m? The specs
say the Z0 of RG-174 is a nominal 50 ohms.
--
73, Cecil http://www.qsl.net/w5dxp



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On Mon, 06 Oct 2003 14:25:33 -0500, Cecil Moore
wrote:

Richard Clark wrote:

everything can be explained by achieving a conjugate match ...

and I see nothing about that in a halfwave line that instead achieves
a Zo match, not a conjugate. A conjugate has very specific properties
and you cannot provide an expression that offers the conjugate for the
situation:

You conveniently trimmed off the rest of my statement.

You are welcome.

Let's just juggle the notion of Zo matching out with a slight boundary
change:

source=200 Ohm(resistive)---50 ohm feedline---load=600 Ohm(resistive)

What is the expression you offer to support your statement that yields
the conjugate? Barring an answer, it follows your statement that

everything can be explained by achieving a conjugate match ...
is yet another in a long list of absurdities.

Again, please note that you deliberately snipped the context of that
statement, not a very ethical thing to do.

This time, everyone welcomes it.

Nothing
that you have said is true at the center of the sun. How's that for a
context change?

Hi Cecil,

About average from you except this time you offered no solution for
either context change. As such, it appears your statement
everything can be explained by achieving a conjugate match ...
has no meaning outside of the center of the sun. I will leave that
you cannot demonstrate your statement anywhere in the known universe.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
As such, it appears your statement

everything can be explained by achieving a conjugate match ...

has no meaning outside of the center of the sun.

None of my statements has any meaning outside of the context in which
they are offered (which you conventiently attempt to obscure). It appears
that you do not want to resolve anything. If so, I hope you won't mind
if others resolve your technical problems at the very time that you are
100% resistant to any resolution.
--
73, Cecil http://www.qsl.net/w5dxp



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On Mon, 06 Oct 2003 15:16:04 -0500, Cecil Moore
wrote:
None of my statements has any meaning outside of the context in which
they are offered

Hi Cecil,

Well, as this all thread started from one context:
everything can be explained by achieving a conjugate match
being so encompassing as to enlarge beyond your capacity to explain,
we find ourselves with shortfalls of example to any context. Your
response of a Zo match is an embarrassing example of poor application
for conjugation, so it would appear that even your single context is
meaningless.

73's
Richard Clark, KB7QHC