Analyzing Stub Matching with Reflection Coefficients
 

On 18 Apr 2007 09:54:20 -0700, Keith Dysart wrote:

Opportunity squandered.

Hi Keith,

Was there any doubt about this eventual outcome? No one argues with a
flat-earther except with the expectation of amusement - unless, of
course, the flat-earther is the White House science advisor.

Write for those who read, not for those who squander your effort.

By the way, when I run your LTSpice example I get 10µS of black
screen.

73's
Richard Clark, KB7QHC

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 2:21 pm, Jim Kelley wrote:
Cecil Moore wrote:
Jim Kelley wrote:
Superposition is a mathematical as well as physical operation. You
maintain that the process of adding x to y must somehow change x and y.

Absolutely false, Jim. Please produce my posting that said
that superposition of x and Y *must* somehow change x and y.

I'm sorry. I must have misunderstood what you meant when you angrily
insisted that waves interact.

You must have indeed (deliberately?) misunderstood. If you would quote
me, as you have demanded that I quote you, you would not be so quick
to obfuscate. The key word in your statement of what I said is "must".
I have NEVER said that two waves MUST interact. All I have ever said
is that it is possible for two waves to interact. If only two waves
out of 100 trillion waves interact, then everything I have said is
true and what you have said is false.

I have said just the opposite.

I must admit to not having seen that post.

It's back there somewhere but I will repeat the concept here.

1. Billions of waves don't superpose, i.e. billions of waves don't
interact.

2. Billions of waves superpose without interference, i.e. billions of
waves
don't interact.

3. Billions of waves interfere without interaction.

4. Sometimes two waves interfere with interaction between the two
waves. The interaction results in permanent change. The two reflected
waves involved in the cancellation of reflections at the surface of a
thin film cannot be recovered.

Please stop refusing to produce my postings that you are quoting as
you have a pathologicao tendency to misquote me.
--
73, Cecil, w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 11:54 am, Keith Dysart wrote:
It is unfortunate, but you are back where you started;
choosing not to learn. Opportunity squandered.

And BTW, so are you. You ignored my earlier posting which poked holes
in your model so I am going to repeat it until you respond to it. We
know exactly what happens to the reflected energy when a signal
generator equipped with a circulator and load are used in the
following experiment.

100W SGCL----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100 watts reflected. The
source sources 100 watts and the circulator resistor dissipates 100
watts which is all of the reflected power.

Keith's 70.7V/50 ohm source----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100w reflected. The
current in the source is zero. The source is not only not sourcing any
forward power, it is also not sinking any reflected power. So much for
Keith's source sinking all the reflected power because it's source
impedance is equal to 50 ohms, the Z0 of the transmission line.

Please don't ignore this posting like you did last time.
--
73, Cecil, w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Jim Kelley wrote:
Cecil Moore wrote:

"No waves are harmed in the process" implies that waves can
never be canceled.

No. The fact that waves do not have an effect on other waves does not
mean that their fields don't superpose.

Superposition is a mathematical as well as physical operation. You
maintain that the process of adding x to y must somehow change x and
y. You insist that superposing x and y means that x effects change to
y, and y effects change to x. But the process of superposing x and y
does not have an effect on either x or y. The only effect is we now
have the algebraic sum of x and y.

ac6xg

It has been pointed out to me that Cecil has never used the word
'must' in the context of the above discussion. I will now rewrite my
article deleting the controversial entry . Hopefully the idea that
'waves can interact' can be safely inferred from Cecil's strenuous
argument against the report that waves don't interact.

Cecil Moore wrote:

"No waves are harmed in the process" implies that waves can
never be canceled.

No. The fact that waves do not have an effect on other waves does
not
mean that their fields don't superpose. [i.e. Cecil infers
incorrectly.]

Superposition is a mathematical as well as physical operation.
Because of the fact that the word interact means 'to act upon one
another', your assertion that waves can interact means
x can effect change to y, and y can effect change to x.

Since you insist that waves can have an effect on other waves, then
you should at least be able to detail either mathematically or
phenomenalogically the effect y has on x, and x has on y as well as
provide some natural process that would cause this effect. Please
elaborate. Thanks.

ac6xg

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 4:06 pm, Richard Clark wrote:
On 18 Apr 2007 09:54:20 -0700, Keith Dysart wrote:

Opportunity squandered.

Hi Keith,

Was there any doubt about this eventual outcome? No one argues with a
flat-earther except with the expectation of amusement - unless, of
course, the flat-earther is the White House science advisor.

Write for those who read, not for those who squander your effort.

The larger efforts are done for a few reasons:
- my learning. It helps to think out the problem and attempt to
articulate it. And I have started experimenting with Spice many years
after I last tried it. It is much more usable now.
- others. I hope that there are some lurkers and others who can learn
something from the musings.
- and perhaps Cecil will learn, which would help the larger community
by reducing the amount of incorrect information being promulgated.

By the way, when I run your LTSpice example I get 10µS of black
screen.

That usually occurs because LTSpice can not find the .plt file or it
has a syntax error. It needs to have the same name as the .asc file
and reside in the same directory. I tested by copying the content
from Google Groups. Perhaps that is a path to get the correct
content.

....Keith

Analyzing Stub Matching with Reflection Coefficients
 

On 18 Apr 2007 17:03:40 -0700, Keith Dysart wrote:

By the way, when I run your LTSpice example I get 10=B5S of black
screen.

That usually occurs because LTSpice can not find the .plt file or it
has a syntax error. It needs to have the same name as the .asc file
and reside in the same directory. I tested by copying the content
from Google Groups. Perhaps that is a path to get the correct
content.

.=2E.Keith

Hi Keith,

From your post:
X: ('=B5',0,0,1e-006,1e-005)
it was the occurence of an errant B5.

You may also note similar oddities preceding your closing signature
and the substitution of B5 in the first line above for the extended
character for micro.

Your newsreader is not fully ASCII compliant. I use agent which is
totally text oriented (it does not render HTML unless so ordered).

73's
Richard Clark, KB7QHC

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 5:01 pm, Cecil Moore wrote:
On Apr 18, 11:54 am, Keith Dysart wrote:

It is unfortunate, but you are back where you started;
choosing not to learn. Opportunity squandered.

And BTW, so are you. You ignored my earlier posting which poked holes
in your model so I am going to repeat it until you respond to it. We
know exactly what happens to the reflected energy when a signal
generator equipped with a circulator and load are used in the
following experiment.

Well, we shall see. Let us call this Experiment A.

100W SGCL----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100 watts reflected. The
source sources 100 watts and the circulator resistor dissipates 100
watts which is all of the reflected power.

True, except for one quibble which I will detail near the end of this
post.

Let us call this next one Experiment B.

Keith's 70.7V/50 ohm source----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100w reflected. The
current in the source is zero. The source is not only not sourcing any
forward power, it is also not sinking any reflected power. So much for
Keith's source sinking all the reflected power because it's source
impedance is equal to 50 ohms, the Z0 of the transmission line.

I have never claimed that the source in any way sank the 'reflected
power'.
I have stated that there is no re-reflection of the reflected wave at
the
source. Since the source is matched to the line, the reflection
coefficient is 0 and the wave just .... Well it must go into the
source
since tau is one. But at least it is not reflected when rho is zero.

As you observe for Experiment B, the current is zero so as you
say "The source is not only not sourcing any forward power, it is
also not sinking any reflected power."

Of course the current is also zero at the same point for
Experiment A, so there as well, the source is not only not sourcing
any forward power, it is also not sinking any reflected power.

A bit more analysis for Experiment A yields some more questions.
Terminate the line with a 50 Ohm resistor. The source is now
providing power to the line, there is no reflection on the line and
the circulator dissipates nothing.
Remove the resistor. The reflection returns. The circulator once
again dissipates 100 W. But as you said, in this condition,
"The source is not only not sourcing any forward power, it is also
not sinking any reflected power." So where did that 100 W being
dissipated in the circulator come from?

I suggest a further extension to both Experiment A and
Experiment B. Replace the 1/4 WL stub with a 1 and 1/4 WL
stub. Now, at each 1/4 WL along the line coming back from
the load, no energy is flowing because either the current is
0 or the voltage is 0. So this absence of energy flow happens
not just at the source but repeatedly along the line. This
makes it difficult to accomodate the thought that the
forward or reflected travelling waves are transporting energy
along the line (at least at the quarter wave points).

Now back to the quibble. You said: "The source sources 100 watts
and the circulator resistor dissipates 100 watts which is all of the
reflected power."

It would be more precise to say "The source sources 100 watts
and the circulator resistor dissipates 100 watts which is numerically
equal to the reflected power." I contend that it is this "numerical
equality" that has led many astray into believing that the
circulator is dissipating the "reflected power". But as we have seen,
no energy crosses the 0 current node into the generator so the
"reflected power" can not make it to the circulator (or the source
resistance, if the generator happens to have one).

Please don't ignore this posting like you did last time.

As requested.

....Keith

Analyzing Stub Matching with Reflection Coefficients
 

Richard Clark wrote:

Was there any doubt about this eventual outcome? No one argues with a
flat-earther except with the expectation of amusement - unless, of
course, the flat-earther is the White House science advisor.

Write for those who read, not for those who squander your effort.

By the way, when I run your LTSpice example I get 10µS of black
screen.

73's
Richard Clark, KB7QHC

Oh come now Richard, the White House Science Advisor would never say
that the earth is flat! Obviously our satellites and the shuttle orbit
the earth. He would probably argue that it was only 4000 or so years
old and that man coexisted with the dinosaurs however. And carbon
dating is horribly inaccurate. And forget about all the other isotopes
we use to date with, they are worthless, too.

Oh yeah, and global warming is not happening and weren't these stupid
climate scientists claiming an ice age was upon us in the 70's? They
just can't make up their minds and stick to it even when presented with
new evidence.

tom
K0TAR

Analyzing Stub Matching with Reflection Coefficients
 

Richard Clark wrote:
On 18 Apr 2007 17:03:40 -0700, Keith Dysart wrote:

By the way, when I run your LTSpice example I get 10=B5S of black
screen.
That usually occurs because LTSpice can not find the .plt file or it
has a syntax error. It needs to have the same name as the .asc file
and reside in the same directory. I tested by copying the content
from Google Groups. Perhaps that is a path to get the correct
content.

.=2E.Keith

Hi Keith,

From your post:
X: ('=B5',0,0,1e-006,1e-005)
it was the occurence of an errant B5.

You may also note similar oddities preceding your closing signature
and the substitution of B5 in the first line above for the extended
character for micro.

Your newsreader is not fully ASCII compliant. I use agent which is
totally text oriented (it does not render HTML unless so ordered).

73's
Richard Clark, KB7QHC

Hi Richard,

Very interesting. I also use Agent for reading newsgroups. I copied and
used Keith's long message without the slightest difficulty. Everything
worked as he said it would.

Wonder what is different?

73,
Gene
W4SZ

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 8:16 pm, Richard Clark wrote:
Hi Keith,

From your post: X: ('=B5',0,0,1e-006,1e-005)

it was the occurence of an errant B5.

You may also note similar oddities preceding your closing signature
and the substitution of B5 in the first line above for the extended
character for micro.

Your newsreader is not fully ASCII compliant. I use agent which is
totally text oriented (it does not render HTML unless so ordered).

I am appalled that I am sending such junk, but my environment is
less than it once was. Where once I had Unix and direct feed, I
am now reduced to using WinXP, Internet Explorer and Google for
posting, though I can use Outlook Express to view. I was lulled into
a false sense of security since both render the posts perfectly, but
when I save the Outlook Express, it claims to have received
text/plain but some characters have been replaced. And Google
'show original' does the same. I suppose 3 dots must mean
something to someone so it substitutes the middle one.
Agghhh.

....Keith

Analyzing Stub Matching with Reflection Coefficients
 

"Keith Dysart" wrote in message
oups.com...
On Apr 18, 8:16 pm, Richard Clark wrote:
Hi Keith,

From your post: X: ('=B5',0,0,1e-006,1e-005)

it was the occurence of an errant B5.

You may also note similar oddities preceding your closing signature
and the substitution of B5 in the first line above for the extended
character for micro.

Your newsreader is not fully ASCII compliant. I use agent which is
totally text oriented (it does not render HTML unless so ordered).

I am appalled that I am sending such junk, but my environment is
less than it once was. Where once I had Unix and direct feed, I
am now reduced to using WinXP, Internet Explorer and Google for
posting, though I can use Outlook Express to view. I was lulled into
a false sense of security since both render the posts perfectly, but
when I save the Outlook Express, it claims to have received
text/plain but some characters have been replaced. And Google
'show original' does the same. I suppose 3 dots must mean
something to someone so it substitutes the middle one.
Agghhh.

...Keith


Keith -

I am using Outlook Express for my reader. I had no problems with your post
at all. The simulation ran without a hitch.

Just thought you would like to know.

John

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:
. . .
I have never claimed that the source in any way sank the 'reflected
power'.
I have stated that there is no re-reflection of the reflected wave at
the
source. Since the source is matched to the line, the reflection
coefficient is 0 and the wave just .... Well it must go into the
source
since tau is one. But at least it is not reflected when rho is zero.
. . .

I'm sure you're talking about the electromagnetic wave of E and H fields
and corresponding voltages and currents. But Cecil (and, I'm afraid,
others) also see waves of average power and sometimes energy, which seem
to follow different rules. Just saying "wave" leaves the opportunity for
misinterpretation as a wave of average power, energy, or something else,
and consequent misdirection.

Roy Lewallen, W7EL

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:


I am appalled that I am sending such junk, but my environment is
less than it once was. Where once I had Unix and direct feed, I
am now reduced to using WinXP, Internet Explorer and Google for
posting, though I can use Outlook Express to view. I was lulled into
a false sense of security since both render the posts perfectly, but
when I save the Outlook Express, it claims to have received
text/plain but some characters have been replaced. And Google
'show original' does the same. I suppose 3 dots must mean
something to someone so it substitutes the middle one.
Agghhh.

...Keith


You may want to look at cygwin, which gives you as much unix as you
would like under windows, all the way up to X.

When you can't have the real thing, it's not a bad substitute.

http://www.cygwin.com/

tom
K0TAR

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 2:01 pm, Cecil Moore wrote:

Keith's 70.7V/50 ohm source----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100w reflected. The
current in the source is zero. The source is not only not sourcing any
forward power, it is also not sinking any reflected power.

What complete and utter Texas-size bullsh*t. It's obvious that the
source is sourcing the forward voltage wave, and it's sucking up
entire reverse voltage wave from the line.

From the labs,
Bunsen

Analyzing Stub Matching with Reflection Coefficients
 

Dr. Honeydew wrote:
On Apr 18, 2:01 pm, Cecil Moore wrote:

Keith's 70.7V/50 ohm source----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100w reflected. The
current in the source is zero. The source is not only not sourcing any
forward power, it is also not sinking any reflected power.

What complete and utter Texas-size bullsh*t. It's obvious that the
source is sourcing the forward voltage wave, and it's sucking up
entire reverse voltage wave from the line.

From the labs,
Bunsen

But the propagating waves of average power envisioned by Cecil and some
others, which they measure with their Bird wattmeters, don't follow the
same rules as voltage waves. Unlike voltage waves, which are very well
known and subject to over a century of analysis using well established
mathematics and physical principles, the waves of average power follow
rules which constantly change to suit the needs of the moment. Watterson
fans will recognize the rules for propagating power waves as closely
resembling those of Calvinball.

Roy Lewallen, W7EL

Analyzing Stub Matching with Reflection Coefficients
 

Jim Kelley wrote:
Since you insist that waves can have an effect on other waves, then
you should at least be able to detail either mathematically or
phenomenalogically the effect y has on x, and x has on y as well as
provide some natural process that would cause this effect. Please
elaborate. Thanks.

In the s-parameter equation, b1 = s11(a1) + s12(a2) = 0,
the interaction of s11(a1) and s12(a2) results in wave
cancellation. The effect of each wave on the other is
to reverse the direction and momentum of both waves.

That is what happens at a Z0-match in a transmission
line. That is what happens at the surface of thin-
film when reflections are being canceled.

Again, the redistribution of the wave energy is certainly
an interaction that wouldn't exist with either wave alone.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:
- and perhaps Cecil will learn, which would help the larger community
by reducing the amount of incorrect information being promulgated.

That's pretty arrogant of you, Keith - forgetting the
possibility that you are wrong. This group seems to
contain more omniscient gurus than I ever knew existed.
My other posting proves that your magic source doesn't
dissipate the reflected power.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Roy Lewallen wrote:

rules which constantly change to suit the needs of the moment. Watterson
fans will recognize the rules for propagating power waves as closely
resembling those of Calvinball.

Roy Lewallen, W7EL

Hopefully some of those here will get that. I would be surprised if
it's more than one in four.

tom
K0TAR

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:
I have stated that there is no re-reflection of the reflected wave at
the
source. Since the source is matched to the line, the reflection
coefficient is 0 and the wave just .... Well it must go into the
source
since tau is one. But at least it is not reflected when rho is zero.

But you are missing the point. You say the source is matched
to the line but the source is obviously re-reflecting 100% of the
reflected energy. Your special magic source is doing exactly
the opposite of what you claim it is doing. The calculated
physical reflection coefficient may be 0 but the virtual
reflection coefficient, SQRT(Pref/Pfor), is 1.0. This is
the point I have been making ever since you started posting.

As you observe for Experiment B, the current is zero so as you
say "The source is not only not sourcing any forward power, it is
also not sinking any reflected power."

Of course the current is also zero at the same point for
Experiment A, so there as well, the source is not only not sourcing
any forward power, it is also not sinking any reflected power.

That's again where you are wrong. In Experiment A, the circulator
load resistor is sinking 100W, i.e. 100% of the reflected power.
A bit of modulation will show that the power being sunk by the
circulator load resistor has made a round trip to the end of
the transmission line short and back.

A bit more analysis for Experiment A yields some more questions.
Terminate the line with a 50 Ohm resistor. The source is now
providing power to the line, there is no reflection on the line and
the circulator dissipates nothing.
Remove the resistor. The reflection returns. The circulator once
again dissipates 100 W. But as you said, in this condition,
"The source is not only not sourcing any forward power, it is also
not sinking any reflected power." So where did that 100 W being
dissipated in the circulator come from?

In Experiment A, the source is sourcing 100 watts and the
circulator load resistor is sinking 100 watts after the
round trip delay to the end of the line and back. If the
source signal is modulated, the delay between the source
signal and the dissipated signal is obvious and can be
measured.

I suggest a further extension to both Experiment A and
Experiment B. Replace the 1/4 WL stub with a 1 and 1/4 WL
stub. Now, at each 1/4 WL along the line coming back from
the load, no energy is flowing because either the current is
0 or the voltage is 0. So this absence of energy flow happens
not just at the source but repeatedly along the line. This
makes it difficult to accomodate the thought that the
forward or reflected travelling waves are transporting energy
along the line (at least at the quarter wave points).

The "absence of energy flow" is an illusion. There is 100
joules/sec in the forward wave and 100 joules/sec in the
reflected wave. Since the waves are flowing in opposite
directions, you can argue that there is no *net* energy
flow, but the component wave energy flow is alive and well.

Now back to the quibble. You said: "The source sources 100 watts
and the circulator resistor dissipates 100 watts which is all of the
reflected power."

Yes, in Experiment A but obviously not in Experiment B.
Your source has failed to perform the way you said it would.
As I said in the beginning, there will be re-reflections from
your source. In this case, there is 100% re-reflection.
Real world conditions are not as simple-minded as you say.

It would be more precise to say "The source sources 100 watts
and the circulator resistor dissipates 100 watts which is numerically
equal to the reflected power." I contend that it is this "numerical
equality" that has led many astray into believing that the
circulator is dissipating the "reflected power".

No, modulation on the reflected wave proves that it has made
a round trip to the end of the line and back. There is no
getting around that fact. There is also no getting around
the fact that the energy content of the stub is identical
in both experiments. The number of joules in the stub, in
both cases, is exactly the magnitude needed to support the
100W forward wave and the 100W reflected wave. The energy
in the stub in Experiment A is obviously real. The energy
in the stub in Experiment B is identical to Experiment A.

But as we have seen,
no energy crosses the 0 current node into the generator so the
"reflected power" can not make it to the circulator (or the source
resistance, if the generator happens to have one).

Your "no energy crosses the 0 current node" is just an ignorant
illusion. The forward current and reflected current are alive
and well and simply superpose to a net current of zero at that
point. We are discussing EM wave energy and a boundary condition
for EM waves to exist is that they must travel at c(VF). If they
don't, they are no longer EM waves.

At a current node, forward current equals 1.414 amps at 0 deg.
Reflected current equals 1.414 amps at 180 deg. Of course, the
*net* current is zero but there is no physical impedance discontinuity
to cause any change in the forward and reflected waves at that
point.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Tom Ring wrote:
Oh yeah, and global warming is not happening ...

Global warming started ~18,000 years ago and peaked
~8000 years ago at two degrees above the average
temperature of today.

Global warming started ~130,000 years ago and peaked
~120,000 years ago at two degrees above the average
temperature of today.

We are already two degrees below the peak temperature
of ~8000 years ago. We are already ~8000 years into
the next ice age with about ~80,000 years to go until
the beginning of the next Global Warming period.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Roy Lewallen wrote:
But Cecil (and, I'm afraid,
others) also see waves of average power and sometimes energy, which seem
to follow different rules.

Power and energy are scalars, Roy. Of course, scalars follow
different rules. Maybe the problem is that you are trying
to use phase math on power.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Dr. Honeydew wrote:
Cecil Moore wrote:
A Bird wattmeter reads 100 watts forward and 100w reflected. The
current in the source is zero. The source is not only not sourcing any
forward power, it is also not sinking any reflected power.

What complete and utter Texas-size bullsh*t. It's obvious that the
source is sourcing the forward voltage wave, and it's sucking up
entire reverse voltage wave from the line.

And doing it while magically expending zero energy.
Perpetual motion is possible, after all.

If zero power is being dissipated in the source, it cannot
be sourcing the forward voltage wave and it cannot be
sucking up the reverse voltage wave.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Roy Lewallen wrote:
Unlike voltage waves, which are very well
known and subject to over a century of analysis using well established
mathematics and physical principles, the waves of average power follow
rules which constantly change to suit the needs of the moment.

The rules of waves of average power come from the
field of optics and they haven't changed in many
decades. You see, average power is all that light
physicists can measure. They call it intensity or
irradiance. To deny the body of physics embodied
in optics is ignorant and ridiculous.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Tom Ring wrote:
Roy Lewallen wrote:
rules which constantly change to suit the needs of the moment.
Watterson fans will recognize the rules for propagating power waves as
closely resembling those of Calvinball.

Hopefully some of those here will get that. I would be surprised if
it's more than one in four.

The rules for propagating waves of EM energy have been
nailed down for generations. Optical physicists don't
have the luxury of measuring voltage and current. They
must necessarily measure average power density. They
are quite good at it and their average power density
equations are quite accurate and mature. They obviously
know a lot more about EM waves than most of the posters
here.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Tom Ring wrote:
Roy Lewallen wrote:

rules which constantly change to suit the needs of the moment.
Watterson fans will recognize the rules for propagating power waves as
closely resembling those of Calvinball.

Roy Lewallen, W7EL

Hopefully some of those here will get that. I would be surprised if
it's more than one in four.

Three out of four readers haven't yet figured out how to use Google?
That's pretty grim. "Calvinball" brought about 70,000 hits, or so the
results screen said.

Roy Lewallen, W7EL

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 8:20 pm, Cecil Moore wrote:
Jim Kelley wrote:
Since you insist that waves can have an effect on other waves, then
you should at least be able to detail either mathematically or
phenomenalogically the effect y has on x, and x has on y as well as
provide some natural process that would cause this effect. Please
elaborate. Thanks.

In the s-parameter equation, b1 = s11(a1) + s12(a2) = 0,
the interaction of s11(a1) and s12(a2) results in wave
cancellation. The effect of each wave on the other is
to reverse the direction and momentum of both waves.

That is what happens at a Z0-match in a transmission
line. That is what happens at the surface of thin-
film when reflections are being canceled.

Again, the redistribution of the wave energy is certainly
an interaction that wouldn't exist with either wave alone.
--
73, Cecil http://www.w5dxp.com

Redistribution is an interaction....interesting. But, you were
telling us about how waves interact with other waves. I'm interested
to know what effect x has on y, and vice versa? We have x + y making
z. So after that, tell us how have x and y changed as a result of
their "interaction"?

73, Jim AC6XG

Analyzing Stub Matching with Reflection Coefficients
 

On Thu, 19 Apr 2007 01:25:29 GMT, Gene Fuller
wrote:

On 18 Apr 2007 17:03:40 -0700, Keith Dysart wrote:
.=2E.Keith

Hi Richard,

Very interesting. I also use Agent for reading newsgroups. I copied and
used Keith's long message without the slightest difficulty. Everything
worked as he said it would.

Wonder what is different?

Hi Gene,

Good question. It was just a couple of ripples in the time-space
continuum perhaps. I can't put my finger on any commonality,
especially for the quote above when it is distinctly outside of any
association with an equal symbol.

Having patched up the text files, the modeler works quite nicely. Nice
piece of work.

It puts the popular generic title of "____ for Dummies" to the test;
because if you fill in the blank with Analog, then there is still one
dummy beneath the waves at low tide.

73's
Richard Clark, KB7QHC

Analyzing Stub Matching with Reflection Coefficients
 

Cecil Moore wrote:

Tom Ring wrote:

Roy Lewallen wrote:

rules which constantly change to suit the needs of the moment.
Watterson fans will recognize the rules for propagating power waves
as closely resembling those of Calvinball.


Hopefully some of those here will get that. I would be surprised if
it's more than one in four.


The rules for propagating waves of EM energy have been
nailed down for generations. Optical physicists don't
have the luxury of measuring voltage and current. They
must necessarily measure average power density. They
are quite good at it and their average power density
equations are quite accurate and mature. They obviously
know a lot more about EM waves than most of the posters
here.

Well, that's one who doesn't. Too bad, since Calvinball was a wondrous
game. I miss it.

tom
K0TAR

Analyzing Stub Matching with Reflection Coefficients
 

Jim Kelley wrote:
Redistribution is an interaction....interesting. But, you were
telling us about how waves interact with other waves. I'm interested
to know what effect x has on y, and vice versa? We have x + y making
z. So after that, tell us how have x and y changed as a result of
their "interaction"?

In a transmision line, when z=0, x and y are permanently
changed. Their energy components combine into one re-reflected
wave. The separate identities of x and y disappear at the
instant that z becomes zero.

In order to measure s11 and s12, a2 is turned off. The result is:

a1----|
|----s21(a2)
s11(a1)----|

Note that s11(a1) has already reflected from the impedance
discontinuity and there are no other impedance discontinuities
between it and the source. Should be smooth sailing.

In order to measure s21 and s22, a1 is turned off. The result is:

|----s22(a2)
s12(a2)----|
|----a2

Note that s12(a2) has already passed through the impedance
discontinuity and there are no other impedance discontinuities
between it and the source. Should be smooth sailing.

s11(a1) and s12(a2) are your two waves. They exist and are
so measurable that their measurements results in knowing
the value of s11 and s12.

For b1 = s11(a1) + s12(a2) = 0, s11(a1) and s12(a2) must
be of equal magnitude and opposite phase. That's exactly
what happens at a Z0-match.

s11(a1) and s12(a2) *never* encounter an impedance discontinuity.
They are effects of a1 and a2 encountering an impedance discontinuity.
The only thing s11(a1) and s12(a2) encounter are each other and that
interaction completely changes those two waves. The two waves cancel
and their energy components are re-distributed in the opposite
direction. s11(a1) and s12(a2) never encounter an impedance
discontinuity.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Cecil Moore wrote:
Jim Kelley wrote:
Since you insist that waves can have an effect on other waves, then
you should at least be able to detail either mathematically or
phenomenalogically the effect y has on x, and x has on y as well as
provide some natural process that would cause this effect. Please
elaborate. Thanks.

In the s-parameter equation, b1 = s11(a1) + s12(a2) = 0,
the interaction of s11(a1) and s12(a2) results in wave
cancellation. The effect of each wave on the other is
to reverse the direction and momentum of both waves.

That is what happens at a Z0-match in a transmission
line. That is what happens at the surface of thin-
film when reflections are being canceled.

Again, the redistribution of the wave energy is certainly
an interaction that wouldn't exist with either wave alone.

Cecil,

Do you see the common factor in your response about "wave interaction"?
In all of your examples there is an interface or some sort of
discontinuity. Nobody argues that waves are forever unchanging. However,
those changes take place only through interaction with interfaces or
other discontinuities.

73,
Gene
W4SZ

Analyzing Stub Matching with Reflection Coefficients
 

Cecil Moore wrote:

[snip]

The "absence of energy flow" is an illusion. There is 100
joules/sec in the forward wave and 100 joules/sec in the
reflected wave. Since the waves are flowing in opposite
directions, you can argue that there is no *net* energy
flow, but the component wave energy flow is alive and well.


[snip]

Cecil,

You have made this claim about "component wave energy flow" or a similar
claim on numerous occasions. However, only a few minutes after the
message above, you wrote,

"Power and energy are scalars, Roy. Of course, scalars follow
different rules. Maybe the problem is that you are trying
to use phase math on power."

Help me out. How can we have scalars flowing in opposite directions? If
the waves can interact, as you claim, why does the associated energy
fail to interact and merely pass like ships in the night?

Conservation of energy does not really help the explanation in this
case, as your recently discovered new reference, Principles of Optics by
Born and Wolf, points out.

73,
Gene
W4SZ

Analyzing Stub Matching with Reflection Coefficients
 

Cecil Moore wrote:
Tom Ring wrote:
Roy Lewallen wrote:
rules which constantly change to suit the needs of the moment.
Watterson fans will recognize the rules for propagating power waves
as closely resembling those of Calvinball.

Hopefully some of those here will get that. I would be surprised if
it's more than one in four.

The rules for propagating waves of EM energy have been
nailed down for generations. Optical physicists don't
have the luxury of measuring voltage and current. They
must necessarily measure average power density. They
are quite good at it and their average power density
equations are quite accurate and mature. They obviously
know a lot more about EM waves than most of the posters
here.

Cecil,

I guess you did not believe me when I said a day or two ago that optical
physicists have advanced well beyond the limited capabilities you allow
them. It is true that they don't measure "voltage and current". I don't
even know what voltage and current mean in the standard context of
optics. However, they do measure fields in many ways, and they do use
extensive calculations based on fields.

The measurement tools used at optical frequencies are a bit different
than the measurement tools used for RF, but they are no less capable.

Do you have any connection with "optical physicists" beyond your reading
of Hecht and the Melles Griot website?

73,
Gene
W4SZ

Analyzing Stub Matching with Reflection Coefficients
 

Gene Fuller wrote:
Do you see the common factor in your response about "wave interaction"?
In all of your examples there is an interface or some sort of
discontinuity. Nobody argues that waves are forever unchanging. However,
those changes take place only through interaction with interfaces or
other discontinuities.

I don't disagree and I have gone on record as saying that
reflections only occur at physical impedance discontinuities.
The interaction of s11(a1) and s12(a2) is caused by the
interaction of a1 and a2 with the impedance discontinuity.
There's no doubt about that.

a1 interacts with the impedance discontinuity to cause
s11(a1) and s21(a1). a2 interacts with the impedance
discontinuity to cause s12(a2) and s22(a2). s11(a1),
s12(a2), s21(a1), and s22(a2) are created as a result
(an effect) of the interaction of a1 and a2 with the
impedance discontinuity. I have *NEVER* said that
waves interact with each other in the absence of
an impedance discontinuity. Assertions to that effect
are obfuscations of what I have said.

But even you must realize that the wave component, s11(a1),
*originates* traveling *away from* the impedance discontinuity
as an *EFFECT* of the forward wave, a1, being incident upon
the impedance discontinuity. It is a1 that is incident upon
the impedance discontinuity, not s11(a1). s11(a1) *originates*
at the impedance discontinuity traveling *away from* it and is
*never incident* upon the impedance discontinuity. All s11(a1)
ever encounters is s12(a2) and is canceled on the spot if
s12(a2) is of equal magnitude and opposite phase.

The wave component, s12(a2), *originates* at the impedance
discontinuity traveling *away from* the impedance discontinuity
as an *EFFECT* of the reflected wave, a2, being incident upon
the impedance discontinuity. It is a2 that is incident upon
the impedance discontinuity, not s12(a2). s12(a2) *originates*
at the impedance discontinuity traveling *away from* it and
is *never* incident upon the impedance discontinuity. All it
ever encounters is s11(a1) and is canceled on the spot if
s11(a1) is of equal magnitude and opposite phase.

Arguing that s11(a1) and s12(a2) are incident upon the
impedance discontinuity is obviously false since they
originate traveling *away from* the impedance discontinuity.
It is impossible for signals that originate traveling away
from the impedance discontinuity, to ever be incident upon
the impedance discontinuity. The confusing of cause and effect
is obvious.

So how do you think that signals that originate traveling
*away from* the impedance discontinuity ever can be incident
upon the impedance discontinuity?
--
73, Cecil, w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Cecil, W5DXP wrote:
"The number of joules in the stub, in both cases, is exactly the
magnitude needed to support the 100W forward wave and the 100W reflected
wave."

An energy source of frequency f feeds a 1/4-wave short-circuited stub.
The feedpoint of the stub receives a reflection from the short an
instant later which is practically equal in phase and magnitude to the
energy source.

How much energy will re-enter the source? Practically none because there
is no difference of potential between the reflection and the source.

How much energy will continue to enter the stub? Practically none
because there is no difference of potential between the source and the
reflection.

Best regards, Richard Harrison, KB5WZI

Analyzing Stub Matching with Reflection Coefficients
 

Gene Fuller wrote:
Help me out. How can we have scalars flowing in opposite directions? If
the waves can interact, as you claim, why does the associated energy
fail to interact and merely pass like ships in the night?

That is the nature of EM waves, Gene. EM waves flowing
in opposite directions do NOT interact. However, their
reflected and transmitted components traveling in the
same direction can and do interact at an impedance
discontinuity.

Let's take the following example using a signal generator
and 50 ohm circulator load. rho1 = s11 = 0.707

100W
SGCL---50 ohm line---+---1/2WL 291.4 ohm line---291.4 ohm load
Vfor1=70.7V-- Vfor2=120.7V--
--Vref1=50V --Vref2=0V

Vref1 is the reflected wave that *originates* traveling toward
the source. Its power gets dissipated in the circulator load
resistor. It *NEVER* travels toward the impedance discontinuity.

Vref1 = 0.707(70.7V) = 50V This is the wave that we have
to cancel when we switch the load to 50 ohms. This wave
gets canceled without ever encountering an impedance
discontinuity.

Would you please explain how a wave that originates traveling
away from the impedance discontinuity ever encounters the
impedance discontinuity?
--
73, Cecil, w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Gene Fuller wrote:
I guess you did not believe me when I said a day or two ago that optical
physicists have advanced well beyond the limited capabilities you allow
them.

I know that, Gene. What I have been describing is a history
of the physics of optics. When the theories were first being
developed, all optical physicists could so was measure the
average power density of the light waves. The theories
based on those average power density measurements are
still good today so they must have known what they were
doing. However, if you would like to discredit those great
optical physicists, based on the better measurement
techniques available today, be my guest.
--
73, Cecil, w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Cecil Moore wrote:
Jim Kelley wrote:

Redistribution is an interaction....interesting. But, you were
telling us about how waves interact with other waves. I'm interested
to know what effect x has on y, and vice versa? We have x + y making
z. So after that, tell us how have x and y changed as a result of
their "interaction"?


In a transmision line, when z=0, x and y are permanently
changed. Their energy components combine into one re-reflected
wave. The separate identities of x and y disappear at the
instant that z becomes zero.

In order to measure s11 and s12, a2 is turned off. The result is:

a1----|
|----s21(a2)
s11(a1)----|

Note that s11(a1) has already reflected from the impedance
discontinuity and there are no other impedance discontinuities
between it and the source. Should be smooth sailing.

In order to measure s21 and s22, a1 is turned off. The result is:

|----s22(a2)
s12(a2)----|
|----a2

Note that s12(a2) has already passed through the impedance
discontinuity and there are no other impedance discontinuities
between it and the source. Should be smooth sailing.

s11(a1) and s12(a2) are your two waves. They exist and are
so measurable that their measurements results in knowing
the value of s11 and s12.

For b1 = s11(a1) + s12(a2) = 0, s11(a1) and s12(a2) must
be of equal magnitude and opposite phase. That's exactly
what happens at a Z0-match.

s11(a1) and s12(a2) *never* encounter an impedance discontinuity.
They are effects of a1 and a2 encountering an impedance discontinuity.
The only thing s11(a1) and s12(a2) encounter are each other and that
interaction completely changes those two waves. The two waves cancel
and their energy components are re-distributed in the opposite
direction. s11(a1) and s12(a2) never encounter an impedance
discontinuity.

It certainly is an interesting way of looking at things, Cecil. It's
certainly true that equal and opposite fields cancel. When that's the
case though it becomes problematic arguing that there are waves there.
Did you ever see the movie "A Brilliant Mind" by any chance?

73, ac6xg

Analyzing Stub Matching with Reflection Coefficients
 

Richard Harrison wrote:
How much energy will re-enter the source? Practically none because there
is no difference of potential between the reflection and the source.

Yes, the reflected wave from 50 ohm coax trying to enter Keith's
50 ohm transmitter will be 100% re-reflected in a lossless stub
in complete violation of his assertions which proves that the
reflected wave doesn't see the source impedance and instead sees
the source load-line impedance.

How much energy will continue to enter the stub? Practically none
because there is no difference of potential between the source and the
reflection.

In a lossless stub, zero energy will continue to enter the stub.
In fact, in a lossless stub, the source can theoretically be
completely disconnected and everything remains the same
including 100% re-reflection of reflected waves by the new
open circuit.

Of course, if the stub is real, the losses will take everything
to zero if the stub is disconnected because the source is
supplying the small amount of power lost to dissipation in
a real-world stub which doesn't have an infinite impedance.
--
73, Cecil, w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

Correction: "A Beautiful Mind". Mine is neither beautiful nor
brilliant this morning I'm afraid.

jk

Jim Kelley wrote:

It certainly is an interesting way of looking at things, Cecil. It's
certainly true that equal and opposite fields cancel. When that's the
case though it becomes problematic arguing that there are waves there.
Did you ever see the movie "A Brilliant Mind" by any chance?

73, ac6xg

Analyzing Stub Matching with Reflection Coefficients
 

On Thu, 19 Apr 2007 14:56:33 GMT, Gene Fuller
wrote:

Do you have any connection with "optical physicists" beyond your reading
of Hecht and the Melles Griot website?

Hi Gene,

Aside from the number of us that have experience in the practice?

73's
Richard Clark, KB7QHC