wrote:
Do not be afraid to admit that you have changed the definition of P = V
x I and therefore do not accept the standard definition.

Well, I was taking 'x' as a multiplication sign. Did you mean it as
a cross product sign? In any case, your Vinst is *NET* voltage and
your Iinst is *NET* current. We know that the feedline Z0 forces
Vfwd*Ifwd to be a constant value for a lossless line. We know that
the feedline Z0 forces Vref*Iref to be a constant value for a lossless
line. Vfwd+Vref is the *NET* voltage. Ifwd+Iref is the *NET* current.
Of course, their product, in any form, is going to be *NET* power.

When I learned Pinst = Vinst x Iinst there were no caveats about how
Pinst meant Pnet. Instantaneous energy is flowing or it is not. When
Pinst is 0 for all time, then there is no energy flowing.

But RF energy cannot stand still so if it exists, it must necessarily
flow. If there is no energy flowing, then there is no RF. If there is
no RF, then your statements are irrelevant to this newsgroup. :-)

To satisfy your theory (and minimize double think), you have had to
change this to Pnet is zero to allow these cancelling powers to flow.
So be it.

Your Vinst is *NET* voltage equal to Vfwd+Vref. Your Iinst is *NET*
current equal to Ifwd+Iref. Of course, their product will be *NET*
power. It cannot be anything else.

True, sort of.

Ramo, Whinnery, and Van Duzer will be impressed that you "sort of"
agree with them. :-)

It is not flowing all the way to the end of the
line and then back. There is not enough time for this to happen (on a
multi-wavelength line) since it changes direction every quarter cycle.

Just as I suspected, you are confusing the carriers of the energy with
the energy itself in the waves which moves at the speed of light. A
quarter cycle of time is very, very large compared to the speed of light.

Since water molecules cannot travel at the speed of sound in the ocean,
I assume you would argue that the energy in a tsunami wave cannot travel
at 500 mph, right?

Not quite. Standing voltage and current waves (which are not waves in
the normal sense) can be observed on the line. They can be measured with
real voltage and current instruments; as can real energy flows with
a real (V x I) power meter (but not a 'Bird watt' meter which
is doing something quite different). It happens that if you assume the
existence of forward and reverse voltage and current waves, mathematical
functions can be derived that will produce the same distribution of
voltage and current as observed on the line. This is extraordinarily
convenient some analysis but does not mean that these assumed waves are
real.

So please amaze me with a model that produces standing waves without actual
forward and reflected waves (in a single source, single feedline, single load
system).

A mechanical analogue would be to look at a guy wire on a pole. You can
analyze the forces as two vectors at 90 degrees (or any other angle of
convenience!), but never make the mistake of assuming that there are
actually two guy wires present. Just because it is mathematically
convenient to assume the existence of two vectors does not mean they
exist.

Nobody is rejecting it. If the lossless stub is one second long, it takes
two seconds of *POWER* to bring it to steady-state. If the stub contains
no moving energy, where did all those joules go?

This energy is indeed stored in the stub. None of it moves across zero
voltage or current boundaries.

What exactly, keeps energy from crossing the boundary? Here is an example.

source-------------50 ohm coax--------------+----1/4WL stub-----open

What mechanism of physics keeps energy from crossing the '+' point? Note
that there is no physical impedance discontinuity at point '+'.

This is what I (and Ayn Rand) call "primacy of consciousness" type thinking.
If you believe it strongly enough, your math model will dictate reality.
Something about being able to move mountains with the faith of a grain of
mustard seed. Something about being able to change the SWR by changing the
normalization of a Smith Chart on a sheet of paper. OTOH, I believe in
"primacy of existence", where reality dictates my math models. They may
be wrong but are as close to reality as I can get.

All you have to do to convince me that you are right is explain exactly
how standing waves can be sustained without a forward wave and a reflected
wave (in a system with a single source, single feedline, and single load).
--
73, Cecil http://www.qsl.net/w5dxp
"One thing I have learned in a long life: that all our science, measured
against reality, is primitive and childlike ..." Albert Einstein



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