Mismatched Zo Connectors
 

Jim Kelley wrote:
How much energy is "in the reflected wave" without a circulator load
resistor?

There's the same amount of energy in the reflected wave
either way, with or without a circulator load resistor.
The reflected wave is incapable of looking ahead and
using its free will to decide how much energy to contain
depending upon its future fate. But that is what some
people would have us believe.

Does your question imply: A reflected wave that is
going to be dissipated in a circulator resistor sometime
in the future contains energy but a reflected wave that
is going to be dissipated after the power is turned off
does not contain energy?

In a one second long lossless transmission line, watts
equal joules. A forward wave of 200 watts contains 200
joules of energy. A reflected wave of 100 watts contains
100 joules of energy. Under such conditions, the source
has supplied exactly 300 joules more than has been
delivered to the load, no more and no less. Conservation
of energy strikes again.
--
73, Cecil, http://www.qsl.net/w5dxp

Mismatched Zo Connectors
 

Cecil Moore wrote:

The reflected wave is incapable of looking ahead and
using its free will to decide how much energy to contain
depending upon its future fate. But that is what some
people would have us believe.

Those are the bad people, evidently.

Does your question imply: A reflected wave that is
going to be dissipated in a circulator resistor sometime
in the future contains energy but a reflected wave that
is going to be dissipated after the power is turned off
does not contain energy?

The question implies that there are issues regarding the flow of
energy which you continue to misunderstand. Your answer confirms this.

In a one second long lossless transmission line, watts
equal joules. A forward wave of 200 watts contains 200
joules of energy. A reflected wave of 100 watts contains
100 joules of energy. Under such conditions, the source
has supplied exactly 300 joules more than has been
delivered to the load, no more and no less.

Is your claim that the above describes the system with, or without,
the circulator load?

73, ac6xg

Mismatched Zo Connectors
 

Jim Kelley wrote:
The question implies that there are issues regarding the flow of energy
which you continue to misunderstand. Your answer confirms this.

So please enlighten me. How does a wave know whether to
carry energy or not depending upon its future fate? It
is my understanding that the power in an EM wave is ExH
no matter what its future fate.

Does a laser beam reflected from an ideal mirror carry any
less energy than the forward beam just because it has been
reflected? If so, how does that not violate the conservation
of energy principle?

In a one second long lossless transmission line, watts
equal joules. A forward wave of 200 watts contains 200
joules of energy. A reflected wave of 100 watts contains
100 joules of energy. Under such conditions, the source
has supplied exactly 300 joules more than has been
delivered to the load, no more and no less.

Is your claim that the above describes the system with, or without, the
circulator load?

Yes, in both cases the voltage reflection coefficient
at the load is 0.707 making the power reflection
coefficient = 0.5, i.e. half the power incident upon
the load is reflected.

The system with the circulator load at the signal
generator has the signal generator supplying 200
watts and the circulator load resistor dissipating 100
watts. 'SGCR' stands for a signal generator equipped with
a circulator and circulator load resistor equal to the
Z0 of the feedline. There's 300 joules of energy in the
feedline during steady-state. 100 watts is dissipated
in the load.

200W SGCR-----one second long feedline-------load
Pfor=200W-- --Pref=100W

The system without the circulator and load consists of
a 100 watt source feeding an ideal autotuner tied to
the transmission line. In this case all reflected energy
is re-reflected by the Z0-matched autotuner. 'SGAT' stands
for a signal generator equipped with an ideal autotuner.
There's 300 joules of energy in the feedline during
steady-state. 100 watts is dissipated in the load.

100W SGAT-----one second long feedline-------load
Pfor=200W-- --Pref=100W
--
73, Cecil, http://www.qsl.net/w5dxp

Mismatched Zo Connectors
 

Cecil Moore wrote:

How does a wave know whether to
carry energy or not depending upon its future fate?

Does a laser beam reflected from an ideal mirror carry any
less energy than the forward beam just because it has been
reflected?

What can be said other than; these questions appear to have been posed
by someone who is struggling to understand some pretty simple concepts.

In a one second long lossless transmission line, watts
equal joules. A forward wave of 200 watts contains 200
joules of energy. A reflected wave of 100 watts contains
100 joules of energy. Under such conditions, the source
has supplied exactly 300 joules more than has been
delivered to the load, no more and no less.

Is your claim that the above describes the system with, or without,
the circulator load?


Yes, in both cases the voltage reflection coefficient
at the load is 0.707 making the power reflection
coefficient = 0.5, i.e. half the power incident upon
the load is reflected.

But, is the latter really more than a mathematical convenience? (You
may recall that 'power' isn't something which actually moves in
physical systems. And being a scalar, it can be tricky to do a proper
vector analysis.) How energy moves is dependent upon factors
throughout the entire system - not just at the load.

The system with the circulator load at the signal
generator has the signal generator supplying 200
watts and the circulator load resistor dissipating 100
watts. 'SGCR' stands for a signal generator equipped with
a circulator and circulator load resistor equal to the
Z0 of the feedline. There's 300 joules of energy in the
feedline during steady-state. 100 watts is dissipated
in the load.

200W SGCR-----one second long feedline-------load
Pfor=200W-- --Pref=100W

The system without the circulator and load consists of
a 100 watt source feeding an ideal autotuner tied to
the transmission line. In this case all reflected energy
is re-reflected by the Z0-matched autotuner. 'SGAT' stands
for a signal generator equipped with an ideal autotuner.
There's 300 joules of energy in the feedline during
steady-state. 100 watts is dissipated in the load.

100W SGAT-----one second long feedline-------load
Pfor=200W-- --Pref=100W

Very inventive. The question was posed without a load on the
circulator, not without a circulator. You still haven't answered that
question. Perhaps you wouldn't mind just considering one system at a
time. No sense changing the variables just to make the solution come
out the way we want. Don't they teach you that you're not supposed to
change horses in the middle of a stream out there in Texas? ;-)

So, since we've obviously been talking about the steady state, what's
with all the weird questions about 'how the wave knows' what's going
to happen in the future?

73, ac6xg

Mismatched Zo Connectors
 

Jim Kelley wrote:
Cecil Moore wrote:
What can be said other than; these questions appear to have been posed
by someone who is struggling to understand some pretty simple concepts.

Actually, I am struggling to understand your concepts which
you appear somewhat incapable of putting into words, hence
the total absence of anything technical in your posting.

Is energy-passing-a-point "power" as defined by the IEEE
Dictionary? Does an EM wave possesses ExH amount of power
as the technical references assert?

So, since we've obviously been talking about the steady state, what's
with all the weird questions about 'how the wave knows' what's going to
happen in the future?

Steady-state had a beginning and it will have an end. It
cannot be analyzed without knowing what happened in the
beginning and what will happen in the end. Steady-state
is the rug under which you and others try to sweep the
laws of physics including the conservation of energy
principle. I'm doing what I can to call your bluff.
--
73, Cecil http://www.qsl.net/w5dxp

Mismatched Zo Connectors
 

On Thu, 24 Aug 2006 14:22:24 -0700, Jim Kelley
wrote:

Cecil Moore wrote:

How does a wave know whether to
carry energy or not depending upon its future fate?

Hi Jim,

I don't know how you can pass up all these tarnished jewels.

Energy at the speed of light has no time dimension (Lorenz law) and as
such there is no futurity. No future, no fate - presumptions aside
(or galore, depending upon the source).

Does a laser beam reflected from an ideal mirror carry any
less energy than the forward beam just because it has been
reflected?

Of course it does.

Jim, your question was:

How much energy is "in the reflected wave" without a circulator load
resistor?

and we find, after having gone down the primrose path:

Yes, in both cases the voltage reflection coefficient
at the load is 0.707 making the power reflection
coefficient = 0.5, i.e. half the power incident upon
the load is reflected.

The common finding of an unterminated circulator load would offer
reflections from that port passing back to the apparent source, the
original mismatched load. Hence, that load sees more than 0.707
(whatever) - now from two "sources."

There is one way to prevent this, but Cecil doesn't have enough
experience at the linear bench to come up with that solution.
Certainly I can anticipate his fog of vectors and SWR mechanics with 1
second transmission lines blossoming in the swamp - but a real bench
tech could whip out the solution and make it work with less effort and
certainly not have to cobble up a phonebook thick stack of Xeroxed
proofs.

Very inventive. The question was posed without a load on the
circulator, not without a circulator.

You were expecting something else? ;-)

73's
Richard Clark, KB7QHC

Mismatched Zo Connectors
 

Richard Clark wrote:
There is one way to prevent this, but Cecil doesn't have enough
experience at the linear bench to come up with that solution.

Probably true but I am not looking to solve that non-problem.

The question to be answered is: Is the power in an EM wave
equal to ExH as the textbooks say, or is it zero until
dissipated? Jim obviously has his own personal definition of
"power" that disagrees with The IEEE Dictionary. That is
what he is basing his entire argument on - simple semantics
using special definitions of words.

That's why my argument involves one second long transmission
lines in which power in watts = energy in joules. That's
an argument that is very difficult to sweep under the rug.

The number of joules in a transmission line *ALWAYS* equals
the number of joules not lost to radiation, I^2R, and
dielectric and not yet delivered to the load. And it is
*ALWAYS* equivalent to the sum of the forward and reflected
powers in that particular length of transmission line.
--
73, Cecil http://www.qsl.net/w5dxp

Mismatched Zo Connectors
 

Cecil Moore wrote:

Is energy-passing-a-point "power" as defined by the IEEE
Dictionary? Does an EM wave possesses ExH amount of power
as the technical references assert?

Nothing the IEEE says counters the fact that the mathematical product
of two physical quantities does not and can not physically propagate
through a transmission line. It can also not reflect, refract,
diffract, superpose, or interfere constructively or destructively.
Waves propagate and energy moves. Power is simply the rate at which
energy is transferred or changes form. It is the rate at which
'electric smoke' is liberated from one's aerial so to speak.

Steady-state had a beginning and it will have an end. It
cannot be analyzed without knowing what happened in the
beginning and what will happen in the end.

But there's no dispute about what happens in the beginning or at the
end. It's entirely about what you claim is happening in the steady
state.

Steady-state
is the rug under which you and others try to sweep the
laws of physics including the conservation of energy
principle.

The steady-state condition isn't something which contradicts nature -
it IS nature. Clearly, the only one needing to sweep the laws of
physics under the rug around here is you, Cecil.

73, ac6xg

Mismatched Zo Connectors
 

Cecil Moore wrote:

[snip]

Steady-state had a beginning and it will have an end. It
cannot be analyzed without knowing what happened in the
beginning and what will happen in the end. Steady-state
is the rug under which you and others try to sweep the
laws of physics including the conservation of energy
principle. I'm doing what I can to call your bluff.

Cecil,

Countless mathematicians and scientists would disagree with your
characterization of steady state. Perhaps even a few engineers as well. 8-)

This sort of stuff is thoroughly covered in differential equations
courses and in any physics or engineering course that look at electrical
or mechanical response to impulses and other stimuli. Surely they dealt
with such matters at TAMU.

If you refuse to accept standard technical conventions, then there is
little hope of getting others to agree with you.

73,
Gene
W4SZ

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Jim Kelley wrote:
Nothing the IEEE says counters the fact that the mathematical product of
two physical quantities does not and can not physically propagate
through a transmission line.

Once again you make a statement with which no one has disagreed.
Has anybody in the world said otherwise? I certainly have not,
so your statement appears to be just another one of your straw
men. Energy flowing past a point is defined as *power* at that
fixed point even if it is reflected energy! The fact that you are
forced to misrepresent what I have said speaks volumes.

But there's no dispute about what happens in the beginning or at the
end. It's entirely about what you claim is happening in the steady state.

Exactly what is my claim about what is happening in the steady-
state? In case you misunderstood, here it is again.

What I have said is happening during steady-state is that the
source has supplied exactly the amount of energy contained in
the measured forward wave and the measured reflected wave. That
energy has been delivered to the system by the source but has
not yet reached the load. Occam's razor says that exact amount
of energy is most likely contained in the forward and reflected
waves, not magically somewhere else, e.g. sloshing around between
standing wave nodes as W7EL asserts.

I say the ExH watts exist in the forward wave and the reflected
wave just as the textbooks assert. You seem to be saying that it
isn't there. If it isn't there, where did it go? Conservation of
energy strikes again.
--
73, Cecil http://www.qsl.net/w5dxp