Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 8:45 am, Cecil Moore wrote:
Keith Dysart wrote:
The person who desires to not realize can always build road blocks
to prevent realization.

e.g. like refusing to provide a schematic for the
source. :-)
--
73, Cecil http://www.w5dxp.com

So sad Cecil. If you had just popped open LTspice, you would have seen
the schematic under consideration.

But when you don't want to take a chance on learning, you can refuse
to
jump over the bar no matter how low it is, claiming it is too high.

So sad.

....Keith

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:
Cecil Moore wrote:

Keith Dysart wrote:
The person who desires to not realize can always build road blocks
to prevent realization.

e.g. like refusing to provide a schematic for the
source. :-)

So sad Cecil. If you had just popped open LTspice, you would have seen
the schematic under consideration.

I may have missed it, but to the best of my knowledge,
this is the first time you have mentioned the LTspice
reference. I apologize but I'm retired without access
to spice. Is that schematic available anywhere on the
web? If not, how about emailing me a .jpg copy of it?
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 8:57 am, Cecil Moore wrote:
Keith Dysart wrote:
Some may argue that a perfect generator can not be constructed, but
really that is a matter of cash; with enough cash one can construct
a generator that is arbitrarily close to perfect.

But bears no resemblance to the average amateur radio
transmitter. The *goal* is to explain what happens with
the average amateur radio transmitter. We already have
signal generators with circulator loads that will do
what you are trying to do. So why bother trying to
reinvent the wheel?

You give yourself the perfect out, don't you. You won't study
the simple circuits that can be understand (for which, by the
way a circulator is not required, thus indicating that you do not
yet understand them) because they are not complicated
enough to represent an average amateur radio transmitter, and
you can't study an average amateur radio transmitter because it
is too complicated to be understood.

Conclusion: No need to study. Life is good. No need to understand.

So sad.

....Keith

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:
You give yourself the perfect out, don't you. You won't study
the simple circuits that can be understand (for which, by the
way a circulator is not required, thus indicating that you do not
yet understand them) because they are not complicated
enough to represent an average amateur radio transmitter, and
you can't study an average amateur radio transmitter because it
is too complicated to be understood.

I'm willing to study them if you will only send me a
schematic. But I'm not going to waste a lot of time
on something that is of very limited usefulness. We
already have a model that will eliminate reflections,
i.e. a signal generator equipped with a circulator,
but we don't use such for amateur radio transmitters.
Why invent something else that we don't use for amateur
radio transmitters? Why not choose an actual amateur
radio transmitter to try to understand what happens
with amateur radio transmitters? That seems like a
no-brainer to me.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 9:52 am, Cecil Moore wrote:
Keith Dysart wrote:
You give yourself the perfect out, don't you. You won't study
the simple circuits that can be understand (for which, by the
way a circulator is not required, thus indicating that you do not
yet understand them) because they are not complicated
enough to represent an average amateur radio transmitter, and
you can't study an average amateur radio transmitter because it
is too complicated to be understood.

I'm willing to study them if you will only send me a
schematic. But I'm not going to waste a lot of time
on something that is of very limited usefulness. We
already have a model that will eliminate reflections,
i.e. a signal generator equipped with a circulator,
but we don't use such for amateur radio transmitters.
Why invent something else that we don't use for amateur
radio transmitters? Why not choose an actual amateur
radio transmitter to try to understand what happens
with amateur radio transmitters? That seems like a
no-brainer to me.

Why? You say. Because if one does not understand
how the simple circuits behave, there is no hope for
understanding how something as complex as an
amateur radio transmitter behaves.

Amateur transmitters do not have circulators. If you
don't have the tools to figure out what happens when
a wave is incident on the simplest of generators (an
ideal voltage source in series with a resistor), there
is no way you can figure it out for a more complicated
transmitter.

Start simple, then extend.

To learn what happens with the simplest of generators,
look in any textbook on the subject or google '"lattice
diagram" reflection'. The LTspice simulation I previously
offerred can be used to confirm the results of analysis.

....Keith

PS - The schematic for the generator is as described above.
They are connected to each end of a transmission line as
described in a previous post. Compute how much of the
incident wave is reflected at each end. Choose any
frequency, line length, voltage and waveshape you find
convenient for the generators.

Analyzing Stub Matching with Reflection Coefficients
 

Keith Dysart wrote:
Start simple, then extend.

I'm not stopping you from doing that. Please feel free
to post whatever you choose to post.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 11:27 am, Cecil Moore wrote:
Keith Dysart wrote:
Start simple, then extend.

I'm not stopping you from doing that. Please feel free
to post whatever you choose to post.

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

Opportunity squandered.

....Keith

PS - If you change your mind, do feel free to ask.

Analyzing Stub Matching with Reflection Coefficients
 

On Apr 18, 5:40 am, Keith Dysart wrote:
,,,
Of course the
same holds for the ideal transmission lines and the terminators.
The lack of absolute perfection does not obviate the value
of the thought experiment for furthering understanding.

Actually, Keith, one of the beauties of your proposed experiment is
that the line connecting the generators does NOT have to be lossless.
It need only be uniform. The N-S section does not even have to be
exactly 1/2 wave long; it just needs to be tapped in the center. The
E-W section can be virtually any length, and it doesn't even have to
have the same impedance or loss characteristics as the N-S section.
The generators can be a far cry from perfect; they could just as well
be ideal voltage sources, or ideal current sources, or even ICOM
transmitters; they just need to be the same, and have some way to be
driven out-of-phase. Using line with loss results in the sources
having to deliver a small amount of power, of course, and having the N-
S section differ slightly from 1/2 wavelength just means that the
sources will see a slightly reactive load.

And of course, the value of your experiment is what goes on in the
lines, and has nothing to do with the sources driving them. It's a
beautifully simple experiment that can be produced easily on the
bench, or in a simulator (like the free LTSpice or even RFSim99).
Thanks for offering it, Keith.

Cheers,
Tom

Still waiting for someone to send me an ICOM 706 or whatever that was
so I can measure the source impedance seen at the output terminals
while it's delivering its nominally rated power to the recommended
load...

Analyzing Stub Matching with Reflection Coefficients
 

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

Sorry Keith, From your already lengthy postings, I simply
don't perceive that you have anything new to offer, at
least not to me now in my 8th decade. But I could be wrong,
as could you, so please proceed.
--
73, Cecil http://www.w5dxp.com

Analyzing Stub Matching with Reflection Coefficients
 

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. Must be one of those semantics things
again. I know. Let's agree on a definition. How about the one in
Merriam Websters Collegiate Dictionary, Tenth Edition:
interact: to act upon one another

I have said just the opposite.

I must admit to not having seen that post. On the other hand I do
recall seeing some where you ruthlessly insulted other people who
maintained that position. I believe those are still on Google groups
if you'd like to have a look back.

73, Jim AC6XG