Revisiting the Power Explanation
 

Cecil Moore wrote:
Gene Fuller wrote:
That quote agrees completely with what I said.

Gene, you remind me of an ex-friend of mine who when
asked what would happen if he were caught by his wife
in bed with his girlfriend, said, "I would just
deny it."

You said there is no equation for interference.

Hecht in "Optics" provided the equation that you
said didn't exist. I12 is the symbol for interference
between the I1 and I2 waves.

Cecil,

This is getting good. Are you actually claiming that "I" is the symbol
for "interference"? Betcha it ain't. How does Hecht define I1, I2, and I12?

I have plenty of optics books, but I don't have a copy of Hecht. I don't
plan to buy one. I seriously doubt that he says anything very different
from any other author of optics textbooks.

73,
Gene
W4SZ

Revisiting the Power Explanation
 

Gene Fuller wrote:
This is getting good. Are you actually claiming that "I" is the symbol
for "interference"? Betcha it ain't. How does Hecht define I1, I2, and I12?

I is the symbol for irradiance. I1 is the irradiance in
wave 1. I2 is the irradiance in wave 2. I12 is the symbol
for the interference between wave 1 and wave 2, you know
- the symbol that you said didn't exist.

I have plenty of optics books, but I don't have a copy of Hecht.

So during all these months of denying what Hecht has written,
you have been completely ignorant of what Hecht has written?
Why am I not surprised?
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote:
Gene Fuller wrote:
This is getting good. Are you actually claiming that "I" is the symbol
for "interference"? Betcha it ain't. How does Hecht define I1, I2, and
I12?

I is the symbol for irradiance. I1 is the irradiance in
wave 1. I2 is the irradiance in wave 2. I12 is the symbol
for the interference between wave 1 and wave 2, you know
- the symbol that you said didn't exist.

I have plenty of optics books, but I don't have a copy of Hecht.

So during all these months of denying what Hecht has written,
you have been completely ignorant of what Hecht has written?
Why am I not surprised?

Cecil,

OK, we are getting somewhere. According to the equation, we know that
interference has the same units as irradiance. Interesting. Does that
mean that interference doesn't work for fields? Are there multiple
definitions for interference?

I am not at all ignorant of what Hecht has written, but I will admit to
being ignorant of the exact choice of words he uses.

8-)

73,
Gene
W4SZ

Revisiting the Power Explanation
 

Gene Fuller wrote:
OK, we are getting somewhere. According to the equation, we know that
interference has the same units as irradiance. Interesting. Does that
mean that interference doesn't work for fields? Are there multiple
definitions for interference?

My IEEE Dictionary is 130 miles away so I cannot look
up the technical definition for interference. The units
of irradiance are watts per unit area. In a transmission
line, we can consider the unit area to be constant and
simply drop the units of area. The resultant "irradiance"
equation for transmission line power is:

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

2*SQRT(P1*P2)cos(A) is the interference term in watts
where A is the angle between the two interfering fields.

This is all explained at: http://www.w5dxp.com/energy.htm
If the above equation is followed, adding powers is easier
than superposing voltages and then calculating power.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Cecil Moore wrote in news:DHiPh.3364$YL5.1126
@newssvr29.news.prodigy.net:

....
simply drop the units of area. The resultant "irradiance"
equation for transmission line power is:

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

2*SQRT(P1*P2)cos(A) is the interference term in watts
where A is the angle between the two interfering fields.

Is this what you mean by 'algebraic sum' as in your words 'resultant
disturbance at any point in a medium is the algebraic sum of the separate
constituent waves'?

Owen

Revisiting the Power Explanation
 

On Mar 30, 6:27 pm, Cecil Moore wrote:
Keith Dysart wrote:
Well I guess that settles it. You clearly are not aware of the
methodologies. Even ones that work on the simplest of examples.

Perhaps you could educate me.

I am not convinced

Please provide an
S-Parameter analysis of the math model of the
source that you have refused to provide.

especially when the student who does not know how to solve
the problem attempts to tell the teacher how to do so.

There will be opportunity for education when you are prepared
to act as a student, listen to what the teacher has to say,
think about the information being provided and integrate it
into your knowledge base.

Until then, you are not ready to be educated. Sorry.

Please feel free to come back when you are ready.

....Keith

Revisiting the Power Explanation
 

Owen Duffy wrote:
Cecil Moore wrote:
simply drop the units of area. The resultant "irradiance"
equation for transmission line power is:

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

2*SQRT(P1*P2)cos(A) is the interference term in watts
where A is the angle between the two interfering fields.

Is this what you mean by 'algebraic sum' as in your words 'resultant
disturbance at any point in a medium is the algebraic sum of the separate
constituent waves'?

Of course not. That statement of Hecht's applies to vector
(and phasor) fields. Powers are scalars and must be treated
accordingly.
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

Keith Dysart wrote:
There will be opportunity for education when you are prepared
to act as a student, listen to what the teacher has to say,
think about the information being provided and integrate it
into your knowledge base.

:-) What are you, Keith, a sophomore in junior college?
--
73, Cecil http://www.w5dxp.com

Revisiting the Power Explanation
 

"Cecil Moore" wrote in message
t...
Owen Duffy wrote:
Cecil Moore wrote:
simply drop the units of area. The resultant "irradiance"
equation for transmission line power is:

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

2*SQRT(P1*P2)cos(A) is the interference term in watts
where A is the angle between the two interfering fields.

Is this what you mean by 'algebraic sum' as in your words 'resultant
disturbance at any point in a medium is the algebraic sum of the separate
constituent waves'?

Of course not. That statement of Hecht's applies to vector
(and phasor) fields. Powers are scalars and must be treated
accordingly.

and hence my recommendation to abandon power as a useful method of analyzing
waves in transmission lines. power is a scalar, you can't add power without
resorting to digging out the phase angles that come from the current or
voltage waves. so really that p-total equation is what happens when you add
2 current waves and then convert back to powers... you cancel out a whole
bunch of Z0 terms but end up having to keep that ugly phase related factor.

Revisiting the Power Explanation
 

Dave wrote:
and hence my recommendation to abandon power as a useful method of analyzing
waves in transmission lines.

Dave, try the "Energy Brain Teaser" problem.
--
73, Cecil http://www.w5dxp.com