On Wed, 9 Jun 2010 21:45:05 -0700 (PDT), lu6etj
wrote:

PS: Yes Richard I live outside of Buenos Aires city. I hope you have
been welcome on your visit to Argentine... and... what do you think of
our beautiful girls, ah? ;D

Ah! Cherchez la femme. We did a lot of walking around town (stayed
in the Emperador across from Estación Retiro) and there were certainly
crowds of them on Av (Calle?) Florida and along Av 9 de Julio (24
lanes of traffic as I remember with trying to cross from the Opera
house Teatro Colón). In the back of my mind was that Buenos Aires
enjoys the world's highest pedestrian death rate. One large truck
replaced it horn with the sound of someone screaming. (The memories
are starting to flood back.)

It was strange to see Spanish headlines about the capture of Saddam
Husein in his spider hole. An out-of-America experience much like the
evening when I was standing on the quay in Acapulco, waiting for the
Liberty launch back to my ship, and a wave of talk spread through our
group that Nixon had just resigned.

However, returning to pretty girls, when I was in Caracas ten years
ago, I was told the poor lived up in the hills that surround the city
like a fish bowl and the girls got plenty of exercise climbing them.
Gave them Miss Universe figures.

As for Buenos Aires hospitality, too much food (huge steaks) at the
wrong hours. When we went to a restaurant at 9PM, it was like we were
arriving for high tea. How gauche of us. Later, we were satisfied to
enjoy empanadas in the late afternoon and call it dinner. We also
took the train from Estación Constitución down to La Plata to see the
Catedral. Dinner nearby was Wiener Schnitzel. Enjoyed walking
through Recoleta (and seeing the cemetery). Also got out to Abasto to
see Carlos Gardel's neighborhood (love his Tango, his singing gets
better every year).

It was great!

73's
Richard Clark, KB7QHC

On Jun 9, 9:11*pm, Keith Dysart wrote:
On Jun 9, 8:33*am, Cecil Moore wrote:
It is invalid to try to use superposition on scalar values.

You may wish to rethink this assertion, otherwise...

Go.... Do not pass Go. Do not collect 200$.

Keith, virtually everyone (except you) knows that English is a
contextual language and that the entire context cannot be repeated
every time a sentence is uttered. You know and I know that the context
is EM waves. The obvious context of my statement is: "It is invalid to
try to use EM wave superposition on scalar values, since scalar values
are not EM waves."

If you feel forced to resort to crap like that, it indicates that you
have already lost any argument.
--
73, Cecil, w5dxp.com

On Jun 9, 9:29*pm, Keith Dysart wrote:
Ahhh, so you are only claiming that 'on average', the energy does not
enter the PA or 'on average' the energy is reflected.

Of course, you already knew that because I have never said otherwise.
I have stated my opinion more than once that instantaneous (virtual)
power is not worth discussing. Here is what I said on my web page:

"Please note that any power referred to in this paper is an AVERAGE
POWER. Instantaneous power is beyond the scope of this article,
irrelevant to the following discussion, and "of limited utility"
according to Eugene Hecht. [4]"

I have an ample library and cannot find any reference to instantaneous
(virtual) power other than it is "of limited utility", as Hecht noted.
Most of the references imply that paying close attention to the
reality of instantaneous (virtual) power can lead one down a primrose
path to false assumptions.

The finer grained time domain analysis, reveals that some energy does
enter the PA, but that it comes back out again to keep the average the
same.

So what? If it is not dissipated or radiated, it doesn't matter to
anyone (except you).

It would
be good if you were to articulate these limitations to the readers
to reduce confusion.

I have always said that I was talking about power dissipation in a
source resistor or load resistor (or radiation), but you already knew
that. I have said that instantaneous virtual power is irrelevant and
not worth discussing.

Here is a question for you. Given that P(t)=V(t)*I(t), we measure 10
watts at each of 10 points within a single cm., five just inside a
source and five just outside the source. Does that mean we have 100
watts in that single cm.? What is the physical meaning of being able
to measure an infinite amount of power given an infinite number of
measurement points?
--
73, Cecil, w5dxp.com

On Jun 10, 1:48*am, lu6etj wrote:
"There are no standing waves on a lumped element circuit component.
(In fact, lumped-element circuit theory inherently employs the
cosmological presupposition that the speed of light is infinite, as
every EE sophomore should know. See, e.g., - Electric Circuits, by
J.W. Nilsson, Addison-Wesley, 1983, p. 3.)"

It probably should have said: "By a (possibly invalid) definition
only, there are no standing waves on a lumped element circuit
component, even though standing waves might exist in reality". Note
that Dr. Corum is NOT saying that there are no standing waves. He is
simply repeating the false assumptions of the lumped-element circuit
model. In his other paper, he says that if a circuit is electrically
longer than about 15 degrees and phase is important, the lumped-
element circuit model should not be used.

Any lumped-element circuit analysis can be caused to fail simply by
increasing the source frequency.
--
73, Cecil, w5dxp.com

On Jun 10, 2:55*am, Keith Dysart wrote:
On Jun 9, 2:37*pm, lu6etj wrote:



On 9 jun, 13:23, Cecil Moore wrote:

On Jun 9, 8:26*am, Keith Dysart wrote:

6. Keith, using basic circuit theory, reflection coefficients and
* *analysis in the time domain, shows that Cecil's conclusions do not
* *align with expected behaviours.

I must have missed the posting where you proved RF waves do not obey
the *average* power density (irradiance) equation from "Optics", by
Hecht. Neither Hecht nor I have ever said anything about instantaneous
virtual power except that it is "of limited usefulness". Nothing you
have posted about instantaneous virtual power has disagreed or
disproved anything that I have said about *average* power where I
simply quoted Hecht. I suspect that your instantaneous virtual power
must necessarily obey the conservation of energy principle but I am
not going to waste my time trying to prove it. Hecht and I seem to
agree 100% that *average* energy flow obeys the laws of physics.

May I suggest that you read "Optics", by Hecht and post anything with
which you disagree. I, and others, stopped taking you seriously when
you said that an equal magnitude of the forward Poynting vector and
the reflected Poynting vector proves that zero energy is crossing the
boundary (without adding that it is zero NET energy). You have
probably ruined your technical reputation with such nonsense.
--
73, Cecil, w5dxp.com

Good evening. (sunny and cold day, here)

Superposition works just fine for voltage and current,

And electromagnetic waves... We also study TL in physics with a
electromagnetic model (E-H fields).

Yes, of course.

but is mostly
invalid for power. Attempting to apply superposition to power will
lead to inaccurate results.

Yes. As Cecil pointed, power not apply to superposition because it is
a scalar magnitude.

Not quite. It does not apply to power because it does apply to
voltages.
If one doubles the voltage, one gets 4 times the power. There is no
way to make superposition (which is simply addition) simultaneously
work
for voltage and power.

As for scalars... Superposition works quite fine for circuit analysis
with scalars.

I am curious as to what I wrote on the web page that suggested
disagreement with the superposition principle.

Because my interpretation of this sentences on the wave page:

What happens when the signals from two identical generators
at each end of a transmission line collide in the middle?

Term "collide" without quotes suggest (to me) interaction (as
particles). I learnt travelling waves do not "collides" in space (or
linear mediums), simply they crossing each other (as ghosts).( I do
not be sure about this translation)
or, quoting UCLA web page note, "Wave maintain their integrity upon
overlapping (without themselves being permanently changed)".

Superposition is a mathematical trick that allows the solution of
the problem. It does not mean that the pulses pass through each
other, though that is one of the visualizations. Consider a point
on the line where the current is always 0, no electrons cross
this point nor does any energy. Did the pulses cross through
such a point? The voltage envelope appears to, but does that mean
the pulse did?



Does energy cross the midpoint of the transmission line?
.....
The plot shows that the voltage in the middle of the transmission
line is always zero (that's femtoVolts on the left, not a bad
representation for 0 in a simulation). Recalling that Power =
(Volts times Amps), if the voltage is always 0, then there
is no power. With no power, no energy is crossing the
middle of the transmission line.

My interpretation of last sentence (and reading technical controversy
with Cecil and K1TT in thread) make me think that it does not match to
superposition principle (except when there are not any travelling
waves in system, of course). (I do not considered here spice
application to travelling wave model issues).

Please tell me if you agree with Java applets linked -applied to TL
travelling waves- to clarify my understanding of your proposition.

I have no issues with the applets. They show voltage waves crossing
each other and appropriately use superposition to derive the results.

Like many optical illusions, there are multiple ways to visualize
what is happening. The second one for example can also be seen as
the two pulses bouncing off of each other. The response would be
identical if the transmission line was cut at the point of collision.


only in the very special case of the far end being an open or short
circuit and the line being lossless. simulate it for a more general
case of a load other than those and see what happens.

On 25 mayo, 03:35, Richard Clark wrote:
On Mon, 24 May 2010 17:17:41 -0700 (PDT), lu6etj
wrote:

PSE, with the due respect and consideration toward you an the
distinguished colleagues and friends, Would you mind return to the
original question? (sorry if it is not this the most polite form to
ask it)

Hi Miguel,

I presume by "original question" you mean:

On Mon, 24 May 2010 13:06:19 -0700 (PDT), lu6etj wrote:

Absorb the reflected power or amortiguate the effects of variyng load
impedance?

The answer is YES.

Now, if you mean by absorb that all absorbtion results in heat, then
the answer is NO.

If you mean by absorb that all energy is combined in a load, then the
answer is YES.

The difference between YES and NO is the PHASE differences of the two
energies that are combined.

73's
Richard Clark, KB7QHC

Hello folks. (I am learnig new greetings...)

Hi Cecil:
Yesterday I was making some calculations based in your article "An
energy Analysis of a Simple Ideal Source, Part:1 Zero Average
Interference"
I have checked your and Roy results using three methods: Mathematical
solution using the TL Zin obtained from clássical formulas.
Spice simulation with equivalent lumping element resulting of the
above cited formulas, and Spice simulation with a RG8U TL loaded with
RL's of your and Roy examples..
In all cases results agree between different methods and with your
examples (I do.not want to seem pedantic with this last comment ;) )

For this discussion would be relevant the results corresponding to
sixth column of your article using a quarter wave line.
They a 0 - 8 - 22 - 50 - 88.9 - 128 and 200 W (190 W the last one
with Spice TL simulation).

Since the refflection coefficient has not changed, if I do not
misunderstood the premises, quarter wave line PRs do not seems agree
with the hipothesis of Pref adding in Rs with Pfor. I think that is
what Ro. Lewallen denote in his "Food for thought: Forward and reverse
power" example.
Frankly, I think there are somthing wrong in my interpretation because
you (all) should have already performed these checks. I remember you
have said something about that your work (article) was not finished
yet. I confess actually I have not yet entirely clear your differences
but I hope to capture it more accurately.

73 - Miguel LU6ETJ

PS: Hey Richard, I'm glad you liked our city, girls and steaks :)
well you like Gardel (me too) and I like so much your old and classic
jazz music. Billie Holiday... she is one of my favorites.
A friend of me living in Caracas now tell me the gift of fifteen for
girls consists of the operation to put silicones. must be very
dangerous for heart patients, a lot more dangerous than Buenos Aires
street traffic ;)
(SRI, I can not translate = "waiting for the Liberty launch back to
my ship", give me a hand PSE)

On Thu, 10 Jun 2010 20:04:14 -0700 (PDT), lu6etj
wrote:

(SRI, I can not translate = "waiting for the Liberty launch back to
my ship", give me a hand PSE)

Hi Miguel,

I was in the Navy from 1968 to 1975. Our president Richard Nixon
resigned from the presidency in 1974. My ship was in transit between
Charleston, South Carolina to go to the naval ship yard for overhaul
in Bremerton, Washington (state), near Seattle (where I live).

On the way, we spent 5 days in the harbor of Acapulco. We were
"anchored out," which means resting at anchor in the bay instead of
tied up at a pier.

The only way to get back and forth was by a smaller boat (carries
about 75 people). That boat is called a launch. That name is
qualified with Liberty because those who used it were going on
Liberty. In the Navy, Liberty means "time off" or "free time," which
means we can leave work and do what we want to until 0800 the next
day. If we have to be back by midnight, it is called "Cinderella
Liberty."

I was one of the senior Metrologists in the Fleet Electronics
Calibration Laboratory aboard the USS Holland, AS-32 (now tied up in
retirement in Bremerton). I did precision measurement and calibration
of RF standards and maintained a Cesium Beam Standard (atomic clock)
that set the time for the "Boomers" (nuclear submarines). Later,
after the Navy, I added physical standards (length, pressure, tension,
temperature, torque, smoothness, incline...) to my resumé.

I try to catch as many movies from Argentina as possible (I like
Ricardo Darín as an actor, and love "Nueve Reinas"). One of my
degrees is Cinema (the other is English). Another title I like (since
it is about an out-of-work programmer) is "Una Sombra ya Pronto
Serás." Sometimes that title works here too. Héctor Olivera, the
director, has done some interesting things.

73's
Richard Clark, KB7QHC

On Jun 10, 10:04*pm, lu6etj wrote:
For this discussion would be relevant the results corresponding to
sixth column of your article using a quarter wave line.
They a 0 - 8 - 22 - 50 - 88.9 - 128 and 200 W (190 W the last one
with Spice TL simulation).

I'm sorry, Miguel, using a "quarter wave line" is a mistake. You
should be using a lossless 1/8WL line. The results in my article are
based on a 1/8WL (45 deg) lossless line, NOT on a 1/4WL (90 deg) line.
*Please re-run your Spice simulation using a 1/8WL line* and report
back to us. When the line is 1/8WL long, the reflected wave arrives
back at Rs 90 degrees out of phase with the forward wave and cos(90) =
0, so the interference term is zero and all the reflected power is
dissipated in the source resistor. For the special case where
cos(A)=0, i.e. the interference term is zero, the power density
equation reduces to: Prs = Pfor + Pref + 0

Nowhere in my article did I use a 1/4WL line so please don't say that
your Spice results disagree with my chart. It is perfectly
understandable that your 1/4WL results do not agree with my 1/8WL
results.
--
73, Cecil, w5dxp.com

On 11 jun, 11:06, Cecil Moore wrote:
On Jun 10, 10:04*pm, lu6etj wrote:

For this discussion would be relevant the results corresponding to
sixth column of your article using a quarter wave line.
They a 0 - 8 - 22 - 50 - 88.9 - 128 and 200 W (190 W the last one
with Spice TL simulation).

I'm sorry, Miguel, using a "quarter wave line" is a mistake. You
should be using a *lossless 1/8WL line. The results in my article are
based on a 1/8WL (45 deg) lossless line, NOT on a 1/4WL (90 deg) line.
*Please re-run your Spice simulation using a 1/8WL line* and report
back to us. When the line is 1/8WL long, the reflected wave arrives
back at Rs 90 degrees out of phase with the forward wave and cos(90) =
0, so the interference term is zero and all the reflected power is
dissipated in the source resistor. For the special case where
cos(A)=0, i.e. the interference term is zero, the power density
equation reduces to: Prs = Pfor + Pref + 0

Nowhere in my article did I use a 1/4WL line so please don't say that
your Spice results disagree with my chart. It is perfectly
understandable that your 1/4WL results do not agree with my 1/8WL
results.
--
73, Cecil, w5dxp.com

Yes it is OK I am not saying your article use 1/4, In a previous post
I said with 1/8 lambda TL, results support your idea of Pref
dissipating on Rs (is correct my interpretation of your idea?).
Yesterdey I posted results calculated for a 1/4 lambda TL to comparing
both ponting to 1/4 lambda results did not agree with a Pref
dissipating on RS.
Then, I thought you are not intending generalize the very common
notion of.Pref returnig to generator but seem to me you are
hypothesizing there are different mechanisms dealing with Pref
depending of the line length. Is It OK?

(Meanwhile I will take a look at the new thread to look if I can find
exactly what is the heart of this question ;) )

73 - Miguel - LU6ETJ

PS: Thanks Richard, I would not have guessed it without your help.
Really a very interesting electronics job! I'm glad you're interested
in our films.. Of course here I grew up with the ubiquitous Hollywood
movies and I am very familiar with it and his old and popular TV
series. Before I go to bed this early morning I visited your QTH vía
Google streets panoramic photographies. Also I saw David -K1TTT-
watching his computer screen via his robotic webcam. I shake hands in
front of my PC monitor to greet him but did not see me :D

On Jun 11, 4:11*pm, lu6etj wrote:
Then, I thought you are not intending generalize the very common
notion of.Pref returnig to generator but seem to me you are
hypothesizing there are different mechanisms dealing with Pref
depending of the line length. Is It OK?

Yes, a 1/8WL line is a *SPECIAL CASE* where zero interference exists.
In the power density equation:

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

if A = 90, then cos(A) = 0 and there is no interference term and no
interference. When you go to a 1/4WL line, it is no longer a special
case where cos(A)=0 and I have not published anything on my web page
about that condition.
--
73, Cecil, w5dxp.com