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Old March 27th 08, 01:25 PM posted to rec.radio.amateur.antenna
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Default The Rest of the Story

On Thu, 27 Mar 2008 11:49:03 GMT
Cecil Moore wrote:

Roger Sparks wrote:
The bottom line in a nutshell? I'll try.


Thanks Roger, good stuff and much appreciated.
My digesting of your spread sheets is about to
be interrupted by surgery.


Thanks for the kind words. Sorry to hear about your surgery. I hope it goes well and you have a quick recovery.

During those times, the power applied to
the transmission line is much HIGHER because the reflected wave reflects
from the load and source, and merges/adds to the forward wave from the
source.)


May I suggest that you use the word "redistributed"
instead of "reflected" as does the FSU web page at:

http://micro.magnet.fsu.edu/primer/j...ons/index.html

Clip

I think "redistributed" would be the word if the discontinuity included a resistance. "Reflection" is the historical word for wave reversal and implies a "mirror image", which is not the same as the forward image.

I hope the surgery does not take you away from the discussion for long.

--
73, Roger, W7WKB
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Old March 27th 08, 03:52 PM posted to rec.radio.amateur.antenna
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Roger Sparks wrote:
I think "redistributed" would be the word if the discontinuity
included a resistance. "Reflection" is the historical word for
wave reversal and implies a "mirror image", which is not the same
as the forward image.


What I am suggesting is that "redistribution" be used
instead of "reflection" for cases where there exists
no discontinuity. If the source resistor matches the
Z0 of the feedline, there is no discontinuity and
therefore no conventional reflection, yet there are
cases where reflected energy is redistributed back
toward the load. That reversal appears to be a reflection
but is actually the result of superposition along
with destructive interference between *two* waves.
That is what causes the disparity between the physical
reflection coefficient, (Z1-Z2)/(Z1+Z2), and the virtual
reflection coefficient, SQRT(Pref/Pfor).

I hope the surgery does not take you away from the discussion
for long.


At the least, I should still have one good eye left. ;-)
--
73, Cecil http://www.w5dxp.com
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Old March 27th 08, 04:43 PM posted to rec.radio.amateur.antenna
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Default The Rest of the Story

Cecil Moore wrote:


What I am suggesting is that "redistribution" be used
instead of "reflection" for cases where there exists
no discontinuity.


This is sad.

But I suppose that if you are going to invent new science you might as
well invent new terminology as well. 8-)

Yes, I know that the now-famous FSU web page uses "redistribution". Did
you happen to notice that the page was created by a lab tech and a Java
programmer? Do you suppose Hecht, Born and Wolf, and all of the other
acknowledged experts would support dumping "reflection"?

73,
Gene
W4SZ
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Old March 27th 08, 05:26 PM posted to rec.radio.amateur.antenna
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Gene Fuller wrote:
Yes, I know that the now-famous FSU web page uses "redistribution".
Do you suppose Hecht, Born and Wolf, and all of the other
acknowledged experts would support dumping "reflection"?


I would guess the answer is "yes" when the physical
reflection coefficient is zero - in order to avoid
a logical contradiction.

How does a "reflection" occur when the physical reflection
coefficient is zero, in violation of the wave reflection
model? Why is there often a difference between the
physical reflection coefficient and the virtual
reflection coefficient? Which one is wrong?

The convention that I have adopted is that the word
"reflection" is reserved for single wave events.

For multiple wave events where interference exists,
something besides a simple "reflection" takes place.
The intricate color patterns on the surface of a thin
film of oil floating on a puddle of water are not
simple reflections but instead an interaction of
multiple reflected waves. The resulting image bears
absolutely no resemblance to the incident image.

Following the FSU web page usage, the word "redistribution"
is used for multiple wave interaction events like wave
cancellation. (The words we choose to use to describe the
phenomena have zero effect on the phenomena.)

"A rose by any other name would smell as sweet."
--
73, Cecil http://www.w5dxp.com
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Old March 27th 08, 10:44 PM posted to rec.radio.amateur.antenna
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Gene Fuller wrote:
Did you happen to notice that the page was
created by a lab tech and a Java programmer?


Gene, if a tech asserts a fact and an expert
asserts a falsehood, who are you going to
choose to believe?
--
73, Cecil http://www.w5dxp.com


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Old March 28th 08, 01:38 AM posted to rec.radio.amateur.antenna
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Default The Rest of the Story

On Mar 27, 6:44*pm, Cecil Moore wrote:
Gene Fuller wrote:
Did you happen to notice that the page was
created by a lab tech and a Java programmer?


Gene, if a tech asserts a fact and an expert
asserts a falsehood, who are you going to
choose to believe?


The simulator at that web site does seem to have
its issues. Ask it to simulate 700 nm + 680 nm
at the same amplitude and see if the result
represents reality.

...Keith

PS. The result should look like a 689.8 nm sine
wave of continuously varying amplitude.
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Old March 28th 08, 02:33 AM posted to rec.radio.amateur.antenna
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Keith Dysart wrote:
The simulator at that web site does seem to have
its issues. Ask it to simulate 700 nm + 680 nm
at the same amplitude and see if the result
represents reality.


The duration of each calculation appears to be
about one second and then a reboot.
--
73, Cecil http://www.w5dxp.com
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