Revisiting the Power Explanation
 

Jim Kelley wrote:
... in particular, with regard to interference
as a *cause* for the redirection of energy.

Here we are arguing semantics, not principles, again.
The total destructive interference that occurs during
wave cancellation leaves the associated energy with
no option except to be redistributed to an area of
constructive interference. Hecht says as much in
"Optics".
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Jim Kelley wrote:
If anyone in addition to Cecil thought that I was debating the facts
that Walt presented in Reflections, I apologize.

From "Reflections", by Walter Maxwell, 1st edition
Sec 4.3:

"The destructive interference causes mutual cancellation
of two complementary reflected waves ... Wave interference
between these two complementary waves ... causes a
cancellation of energy flow in the direction toward the
generator."

In the context that I am using the words, either
"superposition" or "interference" could be used. They
are two sides of the same coin.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote:

From "Reflections", by Walter Maxwell, 1st edition
Sec 4.3:

"The destructive interference causes mutual cancellation
of two complementary reflected waves ... Wave interference
between these two complementary waves ... causes a
cancellation of energy flow in the direction toward the
generator."

I don't know exactly what the dots represent above; presumably deleted
words. But perhaps it's best if you allow Walt to speak for himself,
lest you begin another "semantics" argument.

73, AC6XG

"Let's you and him fight." I like that. :-)

Revisiting the Power Explanation
 

Jim Kelley wrote:

Cecil Moore wrote:
Here we are arguing semantics, not principles, again.

I was arguing principles, again.

You have caused me to question the definition of a few
words. You have not caused me to question a single
technical principle. That's 100% pure semantics.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

Jim Kelley wrote:
I don't know exactly what the dots represent above; presumably deleted
words.

Yes, it is common practice to delete words irrelevant
to the point being made.

But perhaps it's best if you allow Walt to speak for himself,

He did - in "Reflections", which I quoted.
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

On Wed, 28 Mar 2007 16:26:10 -0700, Jim Kelley wrote:

Hi Cecil -

We've been over this a hundred times already. The only way to get
past it is for you to try to understand that my comment and Eugene
Hecht's are both true. You need to find a way to understand that
there is no contradiction. You could start by noting that Hecht does
not contradict anything that I said. Nowhere does he claim that
interference redirects energy. That's your claim! And I haven't said
that energy isn't redirected. If redirection of energy takes place,
it takes place by reflection - not interference. It's just basic optics.

73, ac6xg

Sorry Jim, but I take exception to your statement, "If redirection of energy takes place,
it takes place by reflection - not interference."

It is the interference between the forward and reflected voltages and beween the forward and reflected
currents that yields the resultant voltage and current values of rho at the matching point which produces
either a virtual short or a virtual open circuit that causes the re-reflection. I have shown this to be true
in my QEX article of Mar/Apr 1998, entitled, "Examining the Mechanics of Wave Interference in Impedance
Matching. It is also Chapter 23 in Reflections 2.

Using the complex values of rho I have shown the magnitude and phase relationships of the aforementioned
voltages and currents at the stub point that result in a virtual open circuit at the stub point to waves
reflected from a 3:1 mismatched load. The result is no reflections on the line between the stub and the
source, but a 3:1 SWR on the line between the mismatched load and the stub. If you don't have a copy of this
article please let me know and I'll send you one via email.

Walt, W2DU

Revisiting the Power Explanation
 

Cecil Moore wrote:
Jim Kelley wrote:
I don't know exactly what the dots represent above; presumably deleted
words.

Yes, it is common practice to delete words irrelevant
to the point being made.

But perhaps it's best if you allow Walt to speak for himself,

He did - in "Reflections", which I quoted.
--
73, Cecil, w5dxp.com

Does Walt have a point that he is trying to make here, Cecil?

73, ac6xg

Revisiting the Power Explanation
 

Jim Kelley wrote:
Does Walt have a point that he is trying to make here, Cecil?

Yes, but why don't you reply to his posting rather than mine?
--
73, Cecil, w5dxp.com

Revisiting the Power Explanation
 

On Mar 29, 1:38 pm, "John" wrote:
"Keith Dysart" wrote in message

ups.com...

On Mar 25, 8:23 pm, Cecil Moore wrote:
- The power into the 450 Ohm generator resistor is
38.6 Watts

Just to pick your nit, I think you meant 36.8 Watts. That would be closer to
the 36.7 Watts I obtained using a simplified approach.

Cheers,
John

Yes, indeed.

Thanks for checking.

....Keith

Revisiting the Power Explanation
 

On Mar 29, 12:35 pm, Cecil Moore wrote:
Keith Dysart wrote:
But truly, do look up lattice diagrams and learn the technique.
The number of problems that you will be able to solve will go
up significantly.

Since your use of it yielded erroneous results,

I am at a bit of a loss. You don't seem to have a methodology
to produce any results and yet you are sure mine are wrong.

I think
I will pass. However, it appears to be much like the
S-Parameter analysis which does yield correct results.

Feel free to apply any methodology of your choice to
predict the magnitude of the re-reflection. All information
about generator internals has been previously provided.

An S-Parameter analysis indicates that you have made an
error in the reflection coefficient, s11, looking into
the 450 ohm transmission line.

Have you computed the correct result then?

From HP's Ap-Note 95-1,
s11 is defined as the "Input reflection coefficient
with the output port TERMINATED BY A MATCHED LOAD."

You calculated your reflection coefficient with the
output port terminated by a mismatched load. There's
your conceptual error! The reflection coefficient, s11,
at the source is *NOT* the same as the reflection
coefficient at the load.

I am not sure where you are going with this. As you map
the system for s parameter evaluation, which is the two
port network that you are evaluating? The generator?
The load? The line?

Have you told anyone else that an emitter follower with
a 450 ohm resistor in the emitter circuit will eliminate
reflections on all 450 ohm transmission lines?

That is a leap that I wouldn't make. An ideal source, as
used in this example, must be able to both source and sink
current. You will need to specify more for us to determine
whether the circuit you propose will achieve that to a
sufficient degree.

....Keith