Question about "Another look at reflections" article.
 

On May 27, 9:50*am, lu6etj wrote:
Also I am interested in check other values and
conditions in your other article (first part) with 45 degree line.

Sorry, I forgot to comment on this. If the line length is fixed at 45
degrees, the reflected wave arrives back at the 50 ohm source resistor
90 degrees out of phase with the source's forward wave. When two waves
are 90 degrees out of phase, there is zero interference between them
because cos(90) = 0 and the interference term in the following
equation disappears.

Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(theta)

There is no re-reflection of the reflected wave from the 50 ohm source
resistor because it matches the coax Z0. There is no redistribution of
constructive/destructive interference energy because there is zero
interference. Therefore, for the special case where Vfor is 90 degrees
out of phase with Vref at the source resistor, all of the reflected
power will be dissipated in the source resistor.

If the interference at the source resistor is constructive, i.e. less
than 90 degrees difference between Vfor and Vref, the power dissipated
in the source resistor will be all of the reflected power plus some of
the source power.

If the interference at the source resistor between Vfor and Vref is
destructive, i.e. between 90 degrees and 180 degrees, some of the
reflected power will be redistributed (by wave cancellation) back
toward the load.

Note that the I and Q method of transferring two streams of
information on the same carrier relies on this same no interference
(at 90 degrees) concept.
--
73, Cecil, w5dxp.com

Question about "Another look at reflections" article.
 

On May 27, 9:50*am, lu6etj wrote:
I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it.

FYI, It appears that Google has a "Reader" available at the top of the
web page, that has the mark-as-read/unread ability with which one can
keep track of the read/unread postings.
--
73, Cecil, w5dxp.com

Question about "Another look at reflections" article.
 

On 27 mayo, 14:05, Cecil Moore wrote:
On May 27, 9:50*am, lu6etj wrote:

I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it.

FYI, It appears that Google has a "Reader" available at the top of the
web page, that has the mark-as-read/unread ability with which one can
keep track of the read/unread postings.
--
73, Cecil, w5dxp.com

Meanwhile I study carefully your reply and investigate the Google
Reader (thanks for tell me) tell you that one ohm examples are only
because I often work with normalized impedances. I will move me to 50
ohms neighborhood... :)

Question about "Another look at reflections" article.
 

On 27 mayo, 14:05, Cecil Moore wrote:
On May 27, 9:50*am, lu6etj wrote:

I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it.

FYI, It appears that Google has a "Reader" available at the top of the
web page, that has the mark-as-read/unread ability with which one can
keep track of the read/unread postings.
--
73, Cecil, w5dxp.com

Meanwhile I study carefully your reply and investigate the Google
Reader (thanks for tell me) tell you that one ohm examples are only
because I often work with normalized impedances. I will move me to 50
ohms neighborhood... :)

Question about "Another look at reflections" article.
 

On 27 mayo, 14:05, Cecil Moore wrote:
On May 27, 9:50*am, lu6etj wrote:

I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it.

FYI, It appears that Google has a "Reader" available at the top of the
web page, that has the mark-as-read/unread ability with which one can
keep track of the read/unread postings.
--
73, Cecil, w5dxp.com

Meanwhile I study carefully your reply and investigate the Google
Reader (thanks for tell me) tell you that one ohm examples are only
because I often work with normalized impedances. I will move me to 50
ohms neighborhood... :)

Question about "Another look at reflections" article.
 

On 26 mayo, 18:44, Richard Clark wrote:
On Wed, 26 May 2010 11:33:08 -0700 (PDT), lu6etj
wrote:

"Always has been a pleasure for me to read you. I have learning very
much from your enthusiastic discussions. You made me think of things
that I never thought without your help. Thank you."

Hi Miguel,

You are welcome.

My comments (beyond your quote above) were in regard to you observing
the amount of time Walt's topic has been under discussion. *In fact,
the agony of source resistance has been painfully with us for as long
as newsgroups could support the noise bandwidth.

As dangerous as unasked-for advice is, prepare something at your bench
to measure all these contentious issues for yourself. *Force the
issues that are only being discussed rather than measured. *Discover
the roots of what used to be a "hands on" avocation. *Learn the
practical reality in relation to the academic meaning. *Discover the
first principles by making mistakes and having failures that you can
correct in front of you, instead of being assisted by an "expert."
Compare results with like-minded bench workers who can perform the
same examinations you are doing.

This is what Walt did - many times. *His bench work eclipses ALL
discussion of theory. *The irony that inhabits this is that his bench
work may even eclipse his own explanations. *Absolutely no one else
has dared to slide up to the bench to demonstrate that, however. *The
level of "critique" is much like ants scattering at the feet of a
giant.

There is a lot of math thrown against the wall to prove something. *It
may or may not be the same thing. *What it does prove is:
* * * * "Models are doomed to succeed."
This is demonstrated here at least once a week on average, and is even
held up as a hallmark of hazing, initiation, or anti-intellectual
snobbery. *Math/Models/Simulations/Theories serve many religious wars.

73's
Richard Clark, KB7QHC

Hi Richard. thanks for your reply.

I recognize so much the Walter's work as I said in my initial post.
"Another look at reflections" was one of the my most appreciated
readings of my early days as student and Ham.
But without wishing to be flattering ("adulador" in spanish), I feel
in debt with much others works from you (all) (I do not give more
names to not commit injustice omiting anyone).
I believe you are a gifted, brilliant, intelligent and supportive Hams
sharing your knowledge and experience with us. For that, I am/we are
indebted to all of you :)

However, I believe for all reasons given above, you will be capable to
arrive to a good technical/scientific consensus about the matter. We
trust in your ability and capacity to get it.
This is very important for us because not all are capable to develop
theory from empirical working and we need your agreement to study
things that in my experience are very difficult to grasp even for
university graduates...

73

Miguel Ghezzi - LU6ETJ

Question about "Another look at reflections" article.
 

On Thu, 27 May 2010 17:03:28 -0700 (PDT), lu6etj
wrote:

However, I believe for all reasons given above, you will be capable to
arrive to a good technical/scientific consensus about the matter. We
trust in your ability and capacity to get it.

Hi Miguel,

A nice sentiment, but even the most silvered authorities disagree. One
has only to look at the relativist camp vs. the quantum camp in
nuclear physics.

This is very important for us because not all are capable to develop
theory from empirical working and we need your agreement to study
things that in my experience are very difficult to grasp even for
university graduates...

Then, this will be dissappointing. University is for finding your own
way, and that does not come without regrets. There's a maxim that
applies he
"If you haven't failed, you are not trying hard enough."

73's
Richard Clark, KB7QHC

Question about "Another look at reflections" article.
 

On 27 mayo, 22:11, Richard Clark wrote:
On Thu, 27 May 2010 17:03:28 -0700 (PDT), lu6etj
wrote:

However, I believe for all reasons given above, you will be capable to
arrive to a good technical/scientific consensus about the matter. We
trust in your ability and capacity to get it.

Hi Miguel,

A nice sentiment, but even the most silvered authorities disagree. One
has only to look at the relativist camp vs. the quantum camp in
nuclear physics.

This is very important for us because not all are capable to develop
theory from empirical working and we need your agreement to study
things that in my experience are very difficult to grasp even for
university graduates...

Then, this will be dissappointing. *University is for finding your own
way, and that does not come without regrets. *There's a maxim that
applies he
* * * * "If you haven't failed, you are not trying hard enough."

73's
Richard Clark, KB7QHC

Yes Richard. I agree, however I said "even for graduated" ("aún para
graduados" in spanish), but this a radio Amateur group, isn't it...
Hey Richard, do not be hard with us :) your helping is important and
valuable for hundred (if not thousands) of present an future Amateurs.
Thanks again.

Miguel

Question about "Another look at reflections" article.
 

On 27 mayo, 12:34, Cecil Moore wrote:
On May 27, 9:50*am, lu6etj wrote:

I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it. (I hope yours be the only one, I
will review all thread tho chek for others).

I am also using Google since ATT dropped Usenet. I liked Thunderbird a
lot better than Google's usenet interface but I am adapting. The above
information is good to know. Thunderbird has a way to keep up with
unread vs read postings but Google doesn't seem to - at least I don't
know how to do it on Google.

In a early post I wrote = "of course if we insert a circulator to
separate both powers, generator now would see 1 ohm load, could
develope 1 W incident, 0 W reflected (Pn=1W) on circulator input, 0.36
W would be outputting on the other port to render 0.64 W (Pn) to the
load with 1 W Pf and 0,36 W Pr again"
Is this result OK for you?.

The SGCR source is usually designed for 50 ohms, i.e. the signal
generator always "sees" a 50 ohm load because it does not "see" any
reflected energy. The ideal circulator is usually designed with 50 ohm
line and a 50 ohm load resistor. If we could stick with that
particular configuration for the SGCR source, it would aid in my
understanding what is the actual system configuration, i.e. not your
fault but I am confused by your above posting.

I am interested in your optic analogy, I can imagine the load as a
partially reflecting surface, real part of it as absorbance
(transmittance if it was a radiator). line as a unidimensional medium
and reflection as the form of "redistribute energy" (is it OK?) and a
coherent light source for the voltage source, but I am still trying to
visualze the optical equivalent of source resistance and its job to be
a good analog, Also I am interested in check other values and
conditions in your other article (first part) with 45 degree line.

I don't think a laser source handles reflected energy like an RF amp
does. So, to start with, let's avoid reflected energy being incident
upon the laser source. Here is a good example to start with, a 1/4WL
non-reflective coating on glass.

Laser-----air-------|--1/4WL thin-film, r = 1.2222---|---Glass, r =
1.4938---...

The 1/4WL thin-film coating on the glass acts exactly like a 1/4WL
matching section of transmission line. Reflections at the air to thin-
film interface are eliminated by wave cancellation just as the FSU web
page says,

micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/
waveinteractions/index.html

"... when two waves of equal amplitude and wavelength that are 180-
degrees ... out of phase with each other meet, they are not actually
annihilated, ... All of the photon energy present in these waves must
somehow be recovered or redistributed in a new direction, according to
the law of energy conservation ... Instead, upon meeting, the photons
are redistributed to regions that permit constructive interference, so
the effect should be considered as a redistribution of light waves and
photon energy rather than the spontaneous construction or destruction
of light."

Note that the reflection coefficient, r, is 1.0 for air. Thus the
SQRT[(1.0)(1.4938)] = 1.2222 ensures that reflections are eliminated
by the r = 1.2222 thin-film coating.

The same thing happens at the '+' Z0-match in the following RF system.

XMTR---50 ohm coax---+---1/4WL 300 ohm feedline---1800 ohm load

Note that SQRT[(50)(1800)] = 300 ensuring that reflections are
eliminated.
--
73, Cecil, w5dxp.com

May we advance in little steps to ensure we share basic assumptions?

1) I did not think of (or is think on?) a laser source, I was one step
before, I think only of a "coherent" source to match monofrequency
simple AC generator analogy.
2) What would be Rs optical analog?
3) Superposition is a medium phenomenon ¿yes?, for example "eter".
Interference an result of it on a other "thing", for example
photographic plate or screen. Are we agree? K

Question about "Another look at reflections" article.
 

On May 27, 9:10*pm, lu6etj wrote:
On 27 mayo, 12:34, Cecil Moore wrote:



On May 27, 9:50*am, lu6etj wrote:

I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it. (I hope yours be the only one, I
will review all thread tho chek for others).

I am also using Google since ATT dropped Usenet. I liked Thunderbird a
lot better than Google's usenet interface but I am adapting. The above
information is good to know. Thunderbird has a way to keep up with
unread vs read postings but Google doesn't seem to - at least I don't
know how to do it on Google.

In a early post I wrote = "of course if we insert a circulator to
separate both powers, generator now would see 1 ohm load, could
develope 1 W incident, 0 W reflected (Pn=1W) on circulator input, 0..36
W would be outputting on the other port to render 0.64 W (Pn) to the
load with 1 W Pf and 0,36 W Pr again"
Is this result OK for you?.

The SGCR source is usually designed for 50 ohms, i.e. the signal
generator always "sees" a 50 ohm load because it does not "see" any
reflected energy. The ideal circulator is usually designed with 50 ohm
line and a 50 ohm load resistor. If we could stick with that
particular configuration for the SGCR source, it would aid in my
understanding what is the actual system configuration, i.e. not your
fault but I am confused by your above posting.

I am interested in your optic analogy, I can imagine the load as a
partially reflecting surface, real part of it as absorbance
(transmittance if it was a radiator). line as a unidimensional medium
and reflection as the form of "redistribute energy" (is it OK?) and a
coherent light source for the voltage source, but I am still trying to
visualze the optical equivalent of source resistance and its job to be
a good analog, Also I am interested in check other values and
conditions in your other article (first part) with 45 degree line.

I don't think a laser source handles reflected energy like an RF amp
does. So, to start with, let's avoid reflected energy being incident
upon the laser source. Here is a good example to start with, a 1/4WL
non-reflective coating on glass.

Laser-----air-------|--1/4WL thin-film, r = 1.2222---|---Glass, r =
1.4938---...

The 1/4WL thin-film coating on the glass acts exactly like a 1/4WL
matching section of transmission line. Reflections at the air to thin-
film interface are eliminated by wave cancellation just as the FSU web
page says,

micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/
waveinteractions/index.html

"... when two waves of equal amplitude and wavelength that are 180-
degrees ... out of phase with each other meet, they are not actually
annihilated, ... All of the photon energy present in these waves must
somehow be recovered or redistributed in a new direction, according to
the law of energy conservation ... Instead, upon meeting, the photons
are redistributed to regions that permit constructive interference, so
the effect should be considered as a redistribution of light waves and
photon energy rather than the spontaneous construction or destruction
of light."

Note that the reflection coefficient, r, is 1.0 for air. Thus the
SQRT[(1.0)(1.4938)] = 1.2222 ensures that reflections are eliminated
by the r = 1.2222 thin-film coating.

The same thing happens at the '+' Z0-match in the following RF system.

XMTR---50 ohm coax---+---1/4WL 300 ohm feedline---1800 ohm load

Note that SQRT[(50)(1800)] = 300 ensuring that reflections are
eliminated.
--
73, Cecil, w5dxp.com

May we advance in little steps to ensure we share basic assumptions?

1) I did not think of (or is think on?) a laser source, I was one step
before, I think only of a "coherent" source to match monofrequency
simple AC generator analogy.
2) What would be Rs optical analog?
3) Superposition is a medium phenomenon ¿yes?, for example "eter".
Interference an result of it on a other "thing", for example
photographic plate or screen. Are we agree? K