Richard Clark wrote:
Chapter 3. Fig. 3-1 "Complete transmission line circuits"

Been there, done that. It doesn't resemble anything you have said.

Chapter 3. Fig. 3-2 "Equivalent circuits"

Been there, done that. It doesn't resemble anything you have said.

Chapter 4. Section 4.4 "Reflected Waves"
which describes the commonplace that any line terminated in an
impedance not the same as the characteristic of the line produces
reflections.

No argument - simple wave reflection stuff.

It should come as no surprise that this combination of source power
and re-reflected power will produce a resultant that is dependant upon
the length of the line.

No argument - the superposed net total simply becomes the forward power.

This offers how the voltage variation ALONG a transmission line is
function of BOTH source Z and load Z.

Yes, my experiment seemed to support that assertion but you rejected it.
You have rejected every attempt of mine to agree with you. It appears that
your goal is complete and utter rejection by everyone on r.r.a.a before
you will achieve happiness. Good luck - you are well on your way.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

On Wed, 15 Oct 2003 13:43:39 -0500, Cecil Moore
wrote:

Richard Clark wrote:
Chapter 3. Fig. 3-1 "Complete transmission line circuits"

Been there, done that. It doesn't resemble anything you have said.

Chapter 3. Fig. 3-2 "Equivalent circuits"

Been there, done that. It doesn't resemble anything you have said.

Chapter 4. Section 4.4 "Reflected Waves"
which describes the commonplace that any line terminated in an
impedance not the same as the characteristic of the line produces
reflections.

No argument - simple wave reflection stuff.

It should come as no surprise that this combination of source power
and re-reflected power will produce a resultant that is dependant upon
the length of the line.

No argument - the superposed net total simply becomes the forward power.

This offers how the voltage variation ALONG a transmission line is
function of BOTH source Z and load Z.

Yes, my experiment seemed to support that assertion but you rejected it.
You have rejected every attempt of mine to agree with you. It appears that
your goal is complete and utter rejection by everyone on r.r.a.a before
you will achieve happiness. Good luck - you are well on your way.

Hi Cecil,

My goal is complete? That was demonstrated at the bench long ago.

You mistake abandonment and rejection, but you did answer my final
question. :-)

73's
Richard Clark, KB7QHC

On Wed, 15 Oct 2003 13:34:31 -0500, Cecil Moore
wrote:

Richard Clark wrote:
I have the advantage here. I could be wrong. I could be shown to be
in error in my reading of Chipman. It hasn't happened. There are
many here who hold copies of his work. There are none who dispute my
recitation at any specific point, nor do they offer statements in his
text expressed by him contradicting my interpretation. My advantage
is that so many here are either lazy if I am wrong, or worse, too
ashamed if I am right. And for such a small matter too. ;-)

Your biggest problem is that you absolutely refuse to allow anyone to
agree with you.

Hi Cecil,

The only complaint is the poor quality of such support. I would
prefer more robust coverage than the cut-and-paste variety. Clearly
you fail to even achieve a modicum of similitude to my thesis by
instead re-phrasing it in your own unnecessary elaborations that spin
off the wall into this "model" that proves you wrong (or so Tam would
have us believe). I see you offering no compelling rebuttal to him,
so the quality of effort, consistent with weak snippages from eminent
texts, is poor as I said.

If this is my biggest problem, it doesn't originate from me, but is
imposed upon me.

73's
Richard Clark, KB7QHC

Richard,

Just a few words about modeling. Yes, they built a model of a 4004 before
they made the chip. They stopped doing that somewhere around the 386.

As for my analog simulation, the simulator I am using is distributed by
Linear Technology Inc so that people can model circuits using their chips. A
lot of real world stuff is sort of simulated, where an analog signal is
digitized, and all filtering and other audio stuff is actually done in a
DSP.

If you want to see something that will really blow your mind, check out the
Harris digital AM transmitter; and no, I don't mean a transmitter for
digital audio.

Tam/WB2TT

"Cecil Moore" wrote in message
...
Tarmo Tammaru wrote:
I measured the SWR at the point Cecil proposed. I don't recall him
specifying a transmission line either.

Everything was connected through three foot lengths of RG-400.
According to the guys over on sci.physics.electromag, that is a
long enough length to force a Z0 of 50 ohms upon the distributed
circuit. Is it easy for you to install some coax in your simulation?
--
73, Cecil http://www.qsl.net/w5dxp
Cecil,

There are models for both lossy and non lossy transmission line. I have not
used them, so it might take some learning. I can tell you though that given
a load and transmission line, if you find the Z at the meter with an HP
vector impedance meter, and then put a lumped impedance of that same value
at the meter, you will get the same results. The meter is a crude impedance
meter.

Tam/WB2TT

Richard,

I hope you are not mixing up analog steady state signals and reflections of
pulses. The re reflection of a signal at a source depends not only on the
impedance, but also on the voltage at the source.

Tam/WB2TT
"Richard Clark" wrote in message
...

Actually, several people (W8JI among them) have measured the output
impedance of common amateur linear amplifiers by at least a couple of
methods. The most credible measurements show, interestingly, a value
very close to 50 ohms when the amplifier is adjusted for normal
operation.

[sotto voce] "and yet it moves" - updated to

Of course, it doesn't really matter, but people continue to make a big
deal out of it.

Roy Lewallen, W7EL

On Wed, 15 Oct 2003 06:48:09 -0500, Cecil Moore
wrote:

Richard Clark wrote:
A transmitter is loaded with two components and a meter placed between
them - woohah!

Richard, I've got Chipman's book now. Where does he say that SWR
depends upon the source impedance. He does describe a localized
resonance effect within a transmission line. Are you saying the
source impedance is a causal parameter for that localized resonance
effect?

Not arguing with you - just still trying to understand what you
are saying.

Hi Cecil,

Your "not arguing" is as passive as your not looking at either the
text nor referencing my having answered this time and time befo

Chapter 3. Fig. 3-1 "Complete transmission line circuits"

Chapter 3. Fig. 3-2 "Equivalent circuits"

These may be resourced to the SAME answers to you Oct. 3.

Also introduced to you:

Chapter 4. Section 4.4 "Reflected Waves"
which describes the commonplace that any line terminated in an
impedance not the same as the characteristic of the line produces
reflections. This, of course, is something that you have no differed
upon, but on the same hand, neither have your carried it to its
logical conclusion which this section introduces as material being
prepared for Chapter 8. Also note that this section explicitly
references the figures described above.

The cogent point offered by Chipman (and has been reported here by me
as a quote), that when a reflection occurs at the load and returns to
the source:
"in general will be partially re-reflected there, depending on
the boundary conditions established by the source Impedance Zs."
It should come as no surprise that this combination of source power
and re-reflected power will produce a resultant that is dependant upon
the length of the line. This conforms to the simple mechanics of
interference which has been so ill-abused here.

Also quoted he
Chapter 8. Section 8.2 "The practical importance of standing
wave observations."
where in paragraph (e)
"... when the source impedance is not equal to the characteristic
Impedance of the line, this conclusion does not apply. The
General case is discussed more fully in Chapter 9."

Then of course there is more in Chapter 8
Chapter 8. Section 8.8 "Multiple Reflections."
This material shows the transient analysis and sets up the steady
state analysis already anticipated above in Chapter 9.

Chapter 9. Section 9.10 "Return loss, reflection loss, and
transmission loss."

This gives an equation (which modelers fail to appreciate in lesser
work) that answers my earlier Challenge of how to reveal the
Transmitter's characteristic Z through the measure of line loss due to
mismatch at both ends of the line.

Chapter 10. Section 10.7 "Resonance curve methods for impedance
measurement."

This offers how the voltage variation ALONG a transmission line is
function of BOTH source Z and load Z. This was demonstrated by my
bench example. Roy wanted that expressed as a formula specific to
SWR, but as he stated he wasn't going to have his mind changed, I
deemed it unnecessary to extend the math to perform that chore, and
especially when this assemblage of Chipman's work is both unread, and
when offered in recitation is unresponded to. Such is the quality of
"peer review."

Chipman is but a single source that I have offered, but he does have a
following and his material is written to be accessible.

As I have stated, my advantage is that I could be proven wrong by my
interpretation, but none choose to do so with their own readings from
the same source.

The question that remains:
Do you abandon the topic like the others?

73's
Richard Clark, KB7QHC

On Wed, 15 Oct 2003 17:18:06 -0400, "Tarmo Tammaru"
wrote:

Richard,

I hope you are not mixing up analog steady state signals and reflections of
pulses. The re reflection of a signal at a source depends not only on the
impedance, but also on the voltage at the source.

Tam/WB2TT

Hi Tam,

Found within the body of what I posted:

Then of course there is more in Chapter 8
Chapter 8. Section 8.8 "Multiple Reflections."
This material shows the transient analysis and sets up the steady
state analysis already anticipated above in Chapter 9.

Didn't you say you studied under Chipman? This is HIS material, not
my derivations. Again, if I were wrong, there are enough copy holders
here to correct me. That has not come to pass in lo' these several
months.

73's
Richard Clark, KB7QHC

On Wed, 15 Oct 2003 17:03:00 -0400, "Tarmo Tammaru"
wrote:

Richard,

Just a few words about modeling. Yes, they built a model of a 4004 before
they made the chip. They stopped doing that somewhere around the 386.

As for my analog simulation, the simulator I am using is distributed by
Linear Technology Inc so that people can model circuits using their chips. A
lot of real world stuff is sort of simulated, where an analog signal is
digitized, and all filtering and other audio stuff is actually done in a
DSP.

If you want to see something that will really blow your mind, check out the
Harris digital AM transmitter; and no, I don't mean a transmitter for
digital audio.

Tam/WB2TT


Hi Tam,

I've used many simulators, including Spice and Electronic Workbench.
I've also read and adhere to Robert Pease's comments, a columnist and
engineer extraordinaire who can be just as dismissive about these
tools, especially when they cloud common sense with the impression of
legitimacy through presenting a number on the basis of faulty
presumptions.

For example, there is no way you can simulate a perfect resistor
simply and confirm it at the bench. So which is more important, the
pipe dream of a virtual circuit, or the real circuit that fails to
perform as forecast? I've seen your recitation of equations. I've
seen many like them applied to precision work that falls flat on its
face when they hit the wall of reality. Basically those so-called
simulations frequently fail to attend to many matters that are
unnoticed to 1% accuracy when the equation supplies 6 places of
resolution in perfection. No such thing could ever be duplicated
without further elaboration of the model, and as evidenced by your
example (and the successive iterations), you are in jeopardy of just
such failures in this "proof" offered.

I've measured the Ohm to seven places of resolution and 6 places of
accuracy. Ohm's Law was not enough, but it did guide at every turn in
the road that found error galore. To accomplish it, it took the
understanding of the Galvanic series, temperature, expansion,
humidity, actual power dissipated, noise, drift, as a host of many
sources of error that go unnoticed and un modeled in ad-hoc
simulations. There is of course no demand for such precision to
reveal the characteristic Z of the source, that can be accomplished
far simpler and is documented by the same authorities who took such
care in measuring the Ohm. The point of the matter, and this has been
shown in Chipman, that the presumption of a matching source in the
discussion of SWR is often taken for granted, and then dismissed as a
necessity.

The proof of a simulator is found in its suite of tests that confirm
what is demonstrable. If your simulator cannot predict the loss of
real coaxial line when faced with mismatches at both ends, then it is
not simulating actual performing conditions. You did not express any
condition of source Z within your equations, when if fails from that
reason, it necessarily invalidates the simulation. You claim, and
Cecil says otherwise, that there was no line specified (making the
specification of SWR rather obscure as a model), and as the inclusion
of a line was a necessary correlative to the exhibition of source Z,
it follows that your model is two steps removed from that argument by
your own admission. So, what is this a model of? Just what do you
mean by SWR? Which model is the most perfect if they are all better
than bench measurements? What impelled the process of changing the
model when even the first one is so much better than the bench? The
80386 would have never beat an abacus with those metaphorical
questions hanging over its model.

I've seen digital transmitters. Circuit Cellar Ink has covered this
form of modulation at least half a dozen years ago or more where Don
Lancaster offered that a digital string can present (through a low
pass filter) a power curve with distortion 60dB down (simply a matter
of string length and clocking).

73's
Richard Clark, KB7QHC

originally appeared in the new subject QZH that came as a consequence
of my typing my call FTL and Agent catching it all in with the ALT
key. :-)

On Wed, 15 Oct 2003 17:18:06 -0400, "Tarmo Tammaru"
wrote:

Richard,

I hope you are not mixing up analog steady state signals and reflections of
pulses. The re reflection of a signal at a source depends not only on the
impedance, but also on the voltage at the source.

Tam/WB2TT

Hi Tam,

Found within the body of what I posted:

Then of course there is more in Chapter 8
Chapter 8. Section 8.8 "Multiple Reflections."
This material shows the transient analysis and sets up the steady
state analysis already anticipated above in Chapter 9.

Didn't you say you studied under Chipman? This is HIS material, not
my derivations. Again, if I were wrong, there are enough copy holders
here to correct me. That has not come to pass in lo' these several
months.

73's
Richard Clark, KB7QHC

Richard,

I went to a Bob Pease seminar a few years ago, great guy.

You are missing one of the points of the simulation. I am not trying to
market an SWR meter. I simulated it with ideal parts so that the instrument
is not affecting the reading. How are you going to measure an SWR of 65:1
with a real meter?

I did change the source impedance, and it did not change the SWR within the
limits of what I could resolve. In addition, as I told Slick a couple of
months ago, I used a real meter (Kenwood SW2000) to measure the SWR with two
different source impedances and two different load impedances, and the
source impedance made no difference.

I don't know that the Harris transmitter is the same as what was described
in Circuit Cellar. The Harris has no modulators and no linear amplifiers;
just a bank of 65 CW power modules that get switched on and off and
synthesize the desired envelope power at something like a 20 KHz rate. Sort
of a D/A converter that runs at a power level of 50 KW.