Is the Superposition Principle invalid?
 

Dave wrote:
"Cecil Moore" wrote:
In a lot of ways, standing waves and traveling
waves are opposites.

'standing' waves aren't waves at all, they are figments of your
instrumentation.

Yep, that's another way they are different from
traveling waves. :-)
--
73, Cecil http://www.w5dxp.com

Is the Superposition Principle invalid?
 

Cecil Moore wrote in
:

In a standing wave, the phase is constant.
In a traveling wave the phase is changing.

In a standing wave, the amplitude varies.
In a traveling wave the amplitude is constant.

Cecil, the set of statements above is not true in the general case.

You seem to want to talk principles, then make statements without
qualification that are not true in the general case.

Its all very confusing!

Owen

Is the Superposition Principle invalid?
 

Owen Duffy wrote:
Cecil Moore wrote:
In a standing wave, the phase is constant.
In a traveling wave the phase is changing.

In a standing wave, the amplitude varies.
In a traveling wave the amplitude is constant.

Cecil, the set of statements above is not true in the general case.

Owen, I told you a couple of days ago that I am talking
about average values during steady-state. If me talking
about average values during steady-state gets your
panties all bunched up, I profusely apologize.
--
73, Cecil http://www.w5dxp.com

Is the Superposition Principle invalid?
 

On Mar 31, 9:18 am, Cecil Moore wrote:
Keith Dysart wrote:
Neither of the equations is the "algebraic sum".

Of course not, power does not follow the superposition
principle.

I've reviewed some of your writings and you have said this
at least as far back as 2001. This is good.

So why did I think otherwise? I think it is your reliance
on Ptot = Pfor + Pref. I see this as an expression from
superposition much the same as Vtot = Vfor + Vref, but I
gather from the paper on your web site that you do not,
rather you see it as an expression of conservation of
energy.

From re-reading your paper, it seems that your thinking
all derives from trying to satisfy the principle of
conservation of energy. This is good. There is general
agreement that energy is conserved.

But them I am confused with your ready acceptance of
Ptot = P1 + P2 +/- Pinterference

Given a P1 that actually exists and a P2 that actually
exists it seems to me that Ptot must equal P1 + P2.
Anything else would fail to satisfy the principle of
conservation of energy.

To make the expression work, +/-Pinterference must
be creating or destroying energy. Given my understanding
of the physical world, this seems most unlikely.

Can you elaborate on how +/-Pinterferance creates or
destroys energy while still conserving energy?

....Keith

Is the Superposition Principle invalid?
 

Dave wrote:
"Cecil Moore" wrote in message
...
Gene Fuller wrote:
In a lot of ways, standing waves and traveling
waves are opposites.

'standing' waves aren't waves at all, they are figments of your
instrumentation. simple instrumentation (read light bulb and loop of wire)
that was originally used to 'tune' antennas could detect only the peaks and
dips of the superimposed forward and reflected currents... because these
'looked' like waves that stood still on the line when you plotted them they
became known as 'standing' waves. and this also led to the horrible use of
the 'standing wave ratio' as a measure of how good an antenna was matched to
the feed line. all of this over the years has led hams to consider
'standing' waves as a real thing when it is really just a consequence of the
superposition principle. We would all be much better off if someone many
years ago had labeled the first 'SWR' meter in units of db for measuring
return loss, or v-forward/v-reverse, or some other real physical unit. not
that the meter would function any differently, but we would all be better
off understanding what is really being measured!


Dave,

That is not a quote from me. Those are Cecil's words.


73,
Gene
W4SZ

Is the Superposition Principle invalid?
 

Keith Dysart wrote:
So why did I think otherwise?

Because you have been told by others that I was superposing
powers. It was a false malicious statement.

But them I am confused with your ready acceptance of
Ptot = P1 + P2 +/- Pinterference

If it is good enough for Eugene Hecht, it is good
enough for me. That is essentially the irradiance
from optical physics.

Given a P1 that actually exists and a P2 that actually
exists it seems to me that Ptot must equal P1 + P2.

No, that is superposition of powers, something that is
not valid. The only time that Ptot = P1 + P2 is when
the phase angle between the voltage is 90 degrees and
the interference term is zero.

Anything else would fail to satisfy the principle of
conservation of energy.

No, Ptot = P1 + P2 violates the conservation of principle
if the phase angle between V1 and V2 is not 90 degrees.

To make the expression work, +/-Pinterference must
be creating or destroying energy.

No, there are two Ptotal's, one in each direction in
a transmission line. If a certain value of destructive
interference exists in one direction then an absolutely
equal value of constructive interference has to exist
in the opposite direction in the transmission line.
Since destructive interference = constructive interference,
no energy is created or destroyed.

All this is explained in my energy article.

Can you elaborate on how +/-Pinterferance creates or
destroys energy while still conserving energy?

Transmission line energy is neither created or destroyed.
What is lost in one direction is gained in the
opposite direction. If reflected energy is eliminated
toward the source, it must show up in the forward wave
toward the load. I cannot explain it any better than
these web pages.

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

http://www.mellesgriot.com/products/optics/oc_2_1.htm
--
73, Cecil http://www.w5dxp.com

Is the Superposition Principle invalid?
 

Gene Fuller wrote:
Dave wrote:
"Cecil Moore" wrote:
Gene Fuller wrote:
In a lot of ways, standing waves and traveling
waves are opposites.

That is not a quote from me. Those are Cecil's words.

It doesn't say it is a quote from you, Gene. Your name
is indented three levels. There are no quoted words at
4 levels, so nothing of yours was quoted. Since my
name is at two levels, everything at three levels
(except your name) is a quote of mine. Newsreader
attributions worked exactly as designed.
--
73, Cecil http://www.w5dxp.com

Is the Superposition Principle invalid?
 

Cecil Moore wrote in news:vOzPh.20165$uo3.15642
@newssvr14.news.prodigy.net:

Owen Duffy wrote:
Cecil Moore wrote:
In a standing wave, the phase is constant.
In a traveling wave the phase is changing.

In a standing wave, the amplitude varies.
In a traveling wave the amplitude is constant.

Cecil, the set of statements above is not true in the general case.

Owen, I told you a couple of days ago that I am talking
about average values during steady-state. If me talking
about average values during steady-state gets your
panties all bunched up, I profusely apologize.

if by 'changing' you mean 'changing with displacement or position', to
make these statements true, you must be talking about lossless or
distionless lines. If your entire discussion is premised on this, then
can your methods / formulas solve practical lossy line problems?

Nothing seems complete and self explanatory... so still, I am left
confused.

Owen

Is the Superposition Principle invalid?
 

Owen Duffy wrote:
if by 'changing' you mean 'changing with displacement or position', to
make these statements true, you must be talking about lossless or
distionless lines. If your entire discussion is premised on this, then
can your methods / formulas solve practical lossy line problems?

Of course, that's why the feedpoint impedance of a 1/2WL
dipole is not zero ohms. Approximately 20% of the
energy on the antenna is radiated during steady-state.
--
73, Cecil http://www.w5dxp.com

Is the Superposition Principle invalid?
 

Cecil Moore wrote:
Owen Duffy wrote:
if by 'changing' you mean 'changing with displacement or position', to
make these statements true, you must be talking about lossless or
distionless lines. If your entire discussion is premised on this, then
can your methods / formulas solve practical lossy line problems?

Of course, that's why the feedpoint impedance of a 1/2WL
dipole is not zero ohms. Approximately 20% of the
energy on the antenna is radiated during steady-state.

To answer the question more fully: The title of my energy
article is: "An Energy Analysis at an Impedance Discontinuity
in an RF Transmission Line". Since the analysis is done at
a *point*, what happens somewhere else in a lossy line is
not a consideration. There are essentially no losses at an
impedance discontinuity *point* (or plane).
--
73, Cecil http://www.w5dxp.com