Keith Dysart wrote:
But which one was real?

That's a metaphysical question. First please prove
that you are real. :-)

Use the analysis technique of your choice, but only as long as
it gives you the correct answers.

It has in every case so far. Other techniques, like
using standing-wave current to try to measure the
phase shift through a loading coil, have failed
miserably.
--
73, Cecil, w5dxp.com

On Apr 11, 11:54 am, Cecil Moore wrote:
Keith Dysart wrote:
But which one was real?

That's a metaphysical question.

So it is settled then. There is no NEED for a forward OR reverse
travelling wave. Differential equations rule.

First please prove that you are real. :-)

It doesn't matter if I am real as long as you think I am.

Use the analysis technique of your choice, but only as long as
it gives you the correct answers.

It has in every case so far.

Well, except for the inability to explain where the "reflected
power" goes in the transmitter. Of course this is not an issue
for carefully selected examples where no "reflected power" reaches
the transmitter. A more general analysis technique would not
require such careful selection of examples.

....Keith

Keith Dysart wrote:

...
Well, except for the inability to explain where the "reflected
power" goes in the transmitter. Of course this is not an issue
for carefully selected examples where no "reflected power" reaches
the transmitter. A more general analysis technique would not
require such careful selection of examples.

...Keith


When I fire up the big russian 3.5KW linear into a high swr, I don't
have to guess about where the reflected power is going at the xmitter,
the nice red glow on the plates are an excellent indication when they
begin dumping unknown amounts of power as infrared radiation ... when I
grab the coax (150 ft. run) and feel its warmth, I even wonder about how
much power it takes to elevate it's temp!

JS

John Smith I wrote in news:evj2m0$jb7$1
@nnrp.linuxfan.it:

When I fire up the big russian 3.5KW linear into a high swr, I don't
have to guess about where the reflected power is going at the xmitter,
the nice red glow on the plates are an excellent indication when they
begin dumping unknown amounts of power as infrared radiation ... when I
grab the coax (150 ft. run) and feel its warmth, I even wonder about how
much power it takes to elevate it's temp!

John,

With that insight and rigorous development, it must be time for you to
publish a book.

Owen

Owen Duffy wrote:

...
John,

With that insight and rigorous development, it must be time for you to
publish a book.

Owen

Owen:

How'd you guess?

Title of book, "Spontaneous Thermal Emission of RF Finals and Feedline
in Amateur Radio Systems With No Apparent Cause(s)!"

Trouble is, the book stores keep putting it with the works on fiction :-(

JS

John Smith I wrote in news:evji53$kf9$1
@nnrp.linuxfan.it:

Owen Duffy wrote:

...
John,

With that insight and rigorous development, it must be time for you to
publish a book.

Owen

Owen:

How'd you guess?

Title of book, "Spontaneous Thermal Emission of RF Finals and Feedline
in Amateur Radio Systems With No Apparent Cause(s)!"

Trouble is, the book stores keep putting it with the works on fiction
:-(

John, it will never sell to the amateur market... you need a simple,
catchy title. If it is destined for the fiction category, you could offer
an sub title like "How reflections ruined my PA... from a ham who
survived to tell the REAL story", with "Don't let it happen to you"
emblazened in flouro red across the cover.

Seriously, simple explanations are appealing, they provide content for
discussion by experts on-air, whether they are correct or not. Simple
explanations can be good, but incorrect ones are never good.

Owen

Keith Dysart wrote:
So it is settled then. There is no NEED for a forward OR reverse
travelling wave. Differential equations rule.

Yes, it is settled in your own mind. In my mind,
there is certainly a need for forward and reverse
traveling waves without which standing-waves would
not be possible. If you want to deny the existence
of the cause of standing-waves, there is nothing
I can to stop you.

Well, except for the inability to explain where the "reflected
power" goes in the transmitter. Of course this is not an issue
for carefully selected examples where no "reflected power" reaches
the transmitter. A more general analysis technique would not
require such careful selection of examples.

The more general analysis technique tells us that
the moon is 1000 miles away from the earth. I don't
know how far away the moon is but I know it is not
1000 miles away.
--
73, Cecil, http://www.qsl.net/w5dxp

On Apr 11, 1:06 pm, Cecil Moore wrote:
Keith Dysart wrote:
So it is settled then. There is no NEED for a forward OR reverse
travelling wave. Differential equations rule.

Yes, it is settled in your own mind. In my mind,
there is certainly a need for forward and reverse
traveling waves without which standing-waves would
not be possible. If you want to deny the existence
of the cause of standing-waves, there is nothing
I can to stop you.

My mistake. But it is difficult to know your position when
you don't indicate clearly that you disagree, so I thought
that with your reply you were agreeing. Apologies.

Well, except for the inability to explain where the "reflected
power" goes in the transmitter. Of course this is not an issue
for carefully selected examples where no "reflected power" reaches
the transmitter. A more general analysis technique would not
require such careful selection of examples.

The more general analysis technique tells us that
the moon is 1000 miles away from the earth. I don't
know how far away the moon is but I know it is not
1000 miles away.

This is a bit of a non sequitur. So what is it that you really
disagree with in the analyses performed by myself and others?

Just for clarity, an example problem that has been previously
analysed is the following:
A generator with a 450 Ohm source impedance drives a 450 Ohm
ideal transmission line terminated in 75 Ohms. What is the
magnitude of the re-reflected wave at the generator?

I think you object to computing the amount of the reverse wave
that is reflected at the generator by using the source impedance.
More specifically you do not agree that the reflection
coefficient at the generator can be derived using
RC = (Zsource - Zline)/(Zsource + Zline).
Also, you do not agree that superposition applies at the source.

Given this, you then do not agree with the computations of the
quantity of the reverse wave that is reflected at the source which
then invalidates any further analysis.

Have I managed to capture the essence of your disagreement with
my and others analyses?

Note that these analyses have been performed without the use of
powers or interference so these side issues are not part of this
question.

....Keith

Keith Dysart wrote:
My mistake. But it is difficult to know your position when
you don't indicate clearly that you disagree, so I thought
that with your reply you were agreeing. Apologies.

I don't disagree with anyone's metaphysics. What
you do inside your own mind is none of my business.
(In my mind, I can still dunk a basketball.)

This is a bit of a non sequitur. So what is it that you really
disagree with in the analyses performed by myself and others?

I have told you many times. Bench test measurements
performed over the past 20 years or so prove that it
works only in your mind, not in reality. The source
impedance of a typical ham transmitter remains somewhat
of a mystery during actual operation. The arguments
continue to rage after decades of bench test experiments
and measurements. The pages of QEX are filled with those
arguments.

A generator with a 450 Ohm source impedance ...

False assumption. That transmitters's source impedance
changes away from 450 ohms just as soon as the reflections
arrive incident upon the source, i.e. the source impedance
is a *variable* that depends upon the magnitude and phase
of the reflected wave. If your source impedance is constant,
it doesn't match real-world conditions.

I think you object to computing the amount of the reverse wave
that is reflected at the generator by using the source impedance.

I certainly don't object to your computations but the
results of those computations have been disproved on
the bench using real world ham transmitters over the
past 20 years or so. Your simple mental model doesn't
correspond to reality unless you take some extraordinary
steps which deviate from real-world ham transmitters.
Have you taken the time to review those experiments?
--
73, Cecil http://www.w5dxp.com

On Apr 12, 8:15 am, Cecil Moore wrote:
I have told you many times. Bench test measurements
performed over the past 20 years or so prove that it
works only in your mind, not in reality. The source
impedance of a typical ham transmitter remains somewhat
of a mystery during actual operation. The arguments
continue to rage after decades of bench test experiments
and measurements. The pages of QEX are filled with those
arguments.

So your only beef with my examples is that they do not
accurately model a "typical ham transmitter"?

A generator with a 450 Ohm source impedance ...

False assumption. That transmitters's source impedance
changes away from 450 ohms just as soon as the reflections
arrive incident upon the source, i.e. the source impedance
is a *variable* that depends upon the magnitude and phase
of the reflected wave.

When you say that source impedance is a "variable", do you
mean this for a "typical ham transmitter", or do you assert
that it applies to every generator, even those which can be
accurately modelled with a Thevenin equivalent circuit (as
many signal generators, even TVSGs can)?

I think you object to computing the amount of the reverse wave
that is reflected at the generator by using the source impedance.

I certainly don't object to your computations but the
results of those computations have been disproved on
the bench using real world ham transmitters over the
past 20 years or so.

Which results have been disproved on the bench?

Your simple mental model doesn't
correspond to reality unless you take some extraordinary
steps which deviate from real-world ham transmitters.
Have you taken the time to review those experiments?

Are the experiments documented in Reflections chapter 19 and
19a representative examples?

My read of these chapters is that they offer compelling
argument and evidence (at least for the tube style
transmitters examined) that ham transmitters are linear*,
at least over their normal region of operation.

Is it your assertion that these claims are incorrect?

....Keith

* Don't confuse this use of linear, which is that the
output stage is linear, with whether the input to output
transfer function of the transmitter is linear. The transfer
function may be non-linear even though the output stage is.