On Sun, 28 Nov 2004 16:53:59 -0700, Wes Stewart
wrote:

If you wouild cite the pages to which you refer, I would gladly scan
then to pdf and post them for all to reference.

Hi Wes,

The math is on the bottom of pg. 203 which is supporting Fig. 9-26.

There is also a section entitled 8.8 Multiple reflections on ppg
174...176.

Then there is the specific math of fully specified matches at both
ends, that is at the source and the load, found in Fig. 10-7 that is
supported by discussion on ppg. 225...227.

All of this bears on discussion around and about the necessary
treatment of the Z of the Source, but I haven't supplied all the
citations within this one reference by any means.

Thanx, Wes. You needn't do all these scans. The group needs to do
their own heavy lifting to escape their naivety about source Z.

73's
Richard Clark, KB7QHC

On Mon, 29 Nov 2004 00:28:22 GMT, Richard Clark
wrote:

|On Sun, 28 Nov 2004 16:53:59 -0700, Wes Stewart
|wrote:
|
|If you wouild cite the pages to which you refer, I would gladly scan
|then to pdf and post them for all to reference.
|
|Hi Wes,
|
|The math is on the bottom of pg. 203 which is supporting Fig. 9-26.
|
|There is also a section entitled 8.8 Multiple reflections on ppg
|174...176.
|
|Then there is the specific math of fully specified matches at both
|ends, that is at the source and the load, found in Fig. 10-7 that is
|supported by discussion on ppg. 225...227.
|
|All of this bears on discussion around and about the necessary
|treatment of the Z of the Source, but I haven't supplied all the
|citations within this one reference by any means.
|
|Thanx, Wes. You needn't do all these scans. The group needs to do
|their own heavy lifting to escape their naivety about source Z.

Hi Richard,

I did it anyway. [g] Hope this covers it:

http://users.triconet.org/wesandlind...rdClarkRef.pdf

Regards,

Wes

On Mon, 29 Nov 2004 10:27:37 -0700, Wes Stewart
wrote:
I did it anyway. [g] Hope this covers it:
http://users.triconet.org/wesandlind...rdClarkRef.pdf

Hi Wes,

Thanx very much. I can see one of two results from this general
availability. The readership here can:
1. Avoid it in stunned shame (the embarrassment in coming of age);
2. Accept it as a remarkable revelation (because it's on the web).

I would hope for a third response from those who could argue what
follows from these first principles, but the lazier ones would
complain of my "attitude" and hobble back to their beauty contests on
their crutches. ;-)

To quote one of my favorite authors, Raymond Chandler, when in "The
Big Sleep" Doghouse Reilly is admonished about the same defect, he
avers "I don't mind if you don't like my manners. They're pretty bad.
I grieve over them during the long winter evenings."

73's
Richard Clark, KB7QHC

I offer a third third response.

On p. 175, Chipman states:

"Equation (8.27) demonstrates explicitly that the shape of a standing
wave pattern representing |V(d)| as a function of d on a transmission
line is in no way affected by the quantities Vs, Zs and [rho]s at the
source."

And equation 8.29 on p. 176, the calculation of reflection coefficient,
contains no source-dependent terms. I'm sure that somewhere in the book,
the author derives SWR in terms of reflection coefficient.

These are the facts:

1. The SWR, positions of the standing waves, reflection coefficient seen
looking into the line, impedance seen looking into the line, and dB line
loss are independent of source impedance.
2. The actual amount of power delivered to a line for a given Thevenin
source voltage will, of course, depend on the source impedance, just as
it would if the source were directly connected to a load. Therefore, the
absolute amount of power dissipated in the load depends on source
impedance. The dB line loss, however, doesn't. Also, the length of time
the line requires to reach equilibrium after initially turning on the
source depends on the source impedance.

These can be found, explicitly stated and/or in easily interpreted
equation form, in a host of references.

I see nothing in the text Wes has kindly posted which contradicts these
facts, and I'm sure there's nothing elsewhere in the text that does.

I often have a hard time understanding Richard's postings, so it's
possible that he's not disagreeing with the statements I've made,
either. If so, I apologize for the misinterpretation.

Roy Lewallen, W7EL

Richard Clark wrote:

On Mon, 29 Nov 2004 10:27:37 -0700, Wes Stewart
wrote:

I did it anyway. [g] Hope this covers it:
http://users.triconet.org/wesandlind...rdClarkRef.pdf


Hi Wes,

Thanx very much. I can see one of two results from this general
availability. The readership here can:
1. Avoid it in stunned shame (the embarrassment in coming of age);
2. Accept it as a remarkable revelation (because it's on the web).

I would hope for a third response from those who could argue what
follows from these first principles, but the lazier ones would
complain of my "attitude" and hobble back to their beauty contests on
their crutches. ;-)

To quote one of my favorite authors, Raymond Chandler, when in "The
Big Sleep" Doghouse Reilly is admonished about the same defect, he
avers "I don't mind if you don't like my manners. They're pretty bad.
I grieve over them during the long winter evenings."

73's
Richard Clark, KB7QHC

On Mon, 29 Nov 2004 12:57:16 -0800, Roy Lewallen
wrote:

|I offer a third third response.
|
|On p. 175, Chipman states:
|
|"Equation (8.27) demonstrates explicitly that the shape of a standing
|wave pattern representing |V(d)| as a function of d on a transmission
|line is in no way affected by the quantities Vs, Zs and [rho]s at the
|source."
|
|And equation 8.29 on p. 176, the calculation of reflection coefficient,
|contains no source-dependent terms. I'm sure that somewhere in the book,
|the author derives SWR in terms of reflection coefficient.
|
|These are the facts:
|
|1. The SWR, positions of the standing waves, reflection coefficient seen
|looking into the line, impedance seen looking into the line, and dB line
|loss are independent of source impedance.
|2. The actual amount of power delivered to a line for a given Thevenin
|source voltage will, of course, depend on the source impedance, just as
|it would if the source were directly connected to a load. Therefore, the
|absolute amount of power dissipated in the load depends on source
|impedance. The dB line loss, however, doesn't. Also, the length of time
|the line requires to reach equilibrium after initially turning on the
|source depends on the source impedance.
|
|These can be found, explicitly stated and/or in easily interpreted
|equation form, in a host of references.
|
|I see nothing in the text Wes has kindly posted which contradicts these
|facts, and I'm sure there's nothing elsewhere in the text that does.
|
|I often have a hard time understanding Richard's postings, so it's
|possible that he's not disagreeing with the statements I've made,
|either. If so, I apologize for the misinterpretation.

In an earlier post to this thread, Richard stated:

|"This is yet another of my references that attend to my recent, short
|thread on the nature of power determination error, and mismatched
|loads AND sources. In fact ALL of these references I've offered
|explicitly describe that the source MUST be matched for ANY of these
|equations about transmission lines bandied about to accurately offer
|true answers. The naive presumptions that Source Z is immaterial to
|the outcome of analysis is quite widespread here."

I almost demurred, much as Roy did, because this statement is not
universal, but I held off because I believe (and hope) that Richard is
talking only about *power* measurement errors.

Wes

On Mon, 29 Nov 2004 12:57:16 -0800, Roy Lewallen
wrote:

|I offer a third third response.
|
|On p. 175, Chipman states:
|
|"Equation (8.27) demonstrates explicitly that the shape of a standing
|wave pattern representing |V(d)| as a function of d on a transmission
|line is in no way affected by the quantities Vs, Zs and [rho]s at the
|source."
|
|And equation 8.29 on p. 176, the calculation of reflection coefficient,
|contains no source-dependent terms. I'm sure that somewhere in the book,
|the author derives SWR in terms of reflection coefficient.

Indeed he does---on the next page.

http://users.triconet.org/wesandlind...manPage177.pdf

Equation (8.30)

1 + |rho|
VSWR -------------
1 - |rho|

Thanks.

So between equations 8.29 and 8.30 the author calculates VSWR without
any source-related terms -- as every other textbook author does.

Roy Lewallen, W7EL

Wes Stewart wrote:
On Mon, 29 Nov 2004 12:57:16 -0800, Roy Lewallen
wrote:

|I offer a third third response.
|
|On p. 175, Chipman states:
|
|"Equation (8.27) demonstrates explicitly that the shape of a standing
|wave pattern representing |V(d)| as a function of d on a transmission
|line is in no way affected by the quantities Vs, Zs and [rho]s at the
|source."
|
|And equation 8.29 on p. 176, the calculation of reflection coefficient,
|contains no source-dependent terms. I'm sure that somewhere in the book,
|the author derives SWR in terms of reflection coefficient.

Indeed he does---on the next page.

http://users.triconet.org/wesandlind...manPage177.pdf

Equation (8.30)

1 + |rho|
VSWR -------------
1 - |rho|

Roy Lewallen wrote:
I see nothing in the text Wes has kindly posted which contradicts these
facts, and I'm sure there's nothing elsewhere in the text that does.

None of us are perfect. All of us (except Jim Kelley :-) will admit to
being human, i.e. capable of making a mistake. The Z(s) of the source,
no doubt, has an effect on the power sourced by the source. But the
"power sourced by the source" has no effect on SWR, which is independent
of source impedance. Given a steady-state forward power, nothing else
depends upon source impedance. If a one ohm source is capable of
supplying the same voltage as a one megohm source, the steady-state
results will be identical.

Given any source with any source impedance, there exists a forward
power. Given any forward power, the source impedance during steady-
state is completely irrelevant.
--
73, Cecil http://www.qsl.net/w5dxp

On Mon, 29 Nov 2004 12:57:16 -0800, Roy Lewallen
wrote:

I'm sure that somewhere in the book,
the author derives SWR in terms of reflection coefficient.

Hi Roy,

No doubt. As I am not immediately interested in the reductionist art
of SWR, then the remainder seemed of little relevance to line losses
and the contribution of source Z to power determination error.

You continue, in part quote of a part quote:
representing |V(d)| as a function of d
which given you offer no more comment upon it, gives me the impression
you are unaware of what function d is. The point of the matter is that
this very equation you chose is examined in isolation, by you, but is
returned to on several occasions by Chipman where he quite
"explicitly" exhibits how V(d) ranges wildly for situations where both
ends of the line are terminated by forced mismatches. This is a
uncommon technique for determining SWR (still not my point, but
nonetheless an obvious example).

And yes, I realize
I often have a hard time understanding Richard's postings
and I often grieve over this on long winter evenings. Roy, you are
too coy by half. ;-)

However, your aside into SWR shape and the focus on reductions to
typical applications (source matches line) does leave a dilemma
because there is now conflict between your isolated quote of Chipman
and the demonstration of EZNEC as reported by my late, short lived
thread. I would offer that EZNEC fully supports Chipman's other
comments on this same quoted material you drew from him, and goes to
the matter I offered of an uncommon technique for SWR determination.
My EZNEC reports are also supported by bench results, and other
sources also recited here. All this seems to leave you on the outside
looking in. As it broaches upon topics that you have long cautioned
me that discussion would not "change your mind," I doubt this will go
any further.

73's
Richard Clark, KB7QHC

Once again, it's not clear to me just what you're trying to prove.

Do you disagree with either of the two numbered statements made in my
posting? If so, which part(s) of which one(s) -- I'm sure I can
demonstrate their correctness. If not, we probably don't disagree.

Roy Lewallen, W7EL

Richard Clark wrote:
On Mon, 29 Nov 2004 12:57:16 -0800, Roy Lewallen
wrote:


I'm sure that somewhere in the book,
the author derives SWR in terms of reflection coefficient.


Hi Roy,

No doubt. As I am not immediately interested in the reductionist art
of SWR, then the remainder seemed of little relevance to line losses
and the contribution of source Z to power determination error.

You continue, in part quote of a part quote:

representing |V(d)| as a function of d

which given you offer no more comment upon it, gives me the impression
you are unaware of what function d is. The point of the matter is that
this very equation you chose is examined in isolation, by you, but is
returned to on several occasions by Chipman where he quite
"explicitly" exhibits how V(d) ranges wildly for situations where both
ends of the line are terminated by forced mismatches. This is a
uncommon technique for determining SWR (still not my point, but
nonetheless an obvious example).

And yes, I realize

I often have a hard time understanding Richard's postings

and I often grieve over this on long winter evenings. Roy, you are
too coy by half. ;-)

However, your aside into SWR shape and the focus on reductions to
typical applications (source matches line) does leave a dilemma
because there is now conflict between your isolated quote of Chipman
and the demonstration of EZNEC as reported by my late, short lived
thread. I would offer that EZNEC fully supports Chipman's other
comments on this same quoted material you drew from him, and goes to
the matter I offered of an uncommon technique for SWR determination.
My EZNEC reports are also supported by bench results, and other
sources also recited here. All this seems to leave you on the outside
looking in. As it broaches upon topics that you have long cautioned
me that discussion would not "change your mind," I doubt this will go
any further.

73's
Richard Clark, KB7QHC