what happens to reflected energy ?
 

"K1TTT" wrote
...
On Jul 4, 4:19 pm, "Szczepan Bialek" wrote:

In electromagnetics Maxwell and Heaveside are the experts. Available on
line.

unfortunately you have to learn modern em to know what writings of
maxwell and heaveside to bother believing... they both went through
learning periods before they came to the final transverse wave
formulations. if you read their earlier works you will be mislead
because they were still learning and following dead end paths like
aether theory and fluid analogies.

Maxwell's aether was as perfect solid with the molecular vortices. The
magnetic field was the sum of the molecular.
The Faraday effect was explained. Transverse waves possible. But in solid
possible are also the longitudinal.
Which of them are in reality decide experiments.

Heaviside modified Maxwell' model. His aether is also motionless but withot
the molecular vortices:
http://en.wikisource.org/wiki/Electr..._moving_charge

Now inside the solenoid no rotations. What rotate the polarisation plane?

Heaviside (father of Maxwell' equations) did not understand Maxwell and did
not agree with the rest:

"Prof. Thomson, who otherwise confirms my results, has also extended the
matter by supposing that the medium itself is set in motion, as well as the
electrification. This is somewhat beyond me. I do not yet know certainly
that the ether can move, or its laws of motion if it can. Fresnel thought
the earth could move through the ether without disturbing it; Stokes, that
it carried the ether along with it, by giving irrotational motion to it."

" I must, however, disagree with Prof. Thomson's assumption that the motion
must be irrotational. It would appear, by the above, that this limitation is
unnecessary."

I simply agree with Maxwell, Stokes, Thompson and the rest famous scientists
that no rotational vibrations (transverse waves).

You prefer Heaviside (engineer) and Authors of the textbooks .
S*

what happens to reflected energy ?
 

On Sun, 4 Jul 2010 18:51:19 -0700 (PDT), lu6etj
wrote:

I apologize for my insistence dear Richard, I do not want to be
stubborn but I remember Carl Sagan telling: "Extraordinary claims
require extraordinary evidence"

Hi Miguel,

Sagan never impressed me, and this quote even less. It relies on
mystical explanations when ordinary works quite well.

and my posting about the very large
quantum number of the 3.5 MHz Xmtrs play here the "conservative"
role :)

The link leads to a lot of tedious and pedantic writing.

Your new analogy fails as quickly as the rest, so by extension I must
presume that the work revealed at your link fails too. That is the
usual fate of tying two things together when one is a rhetorical
anchor.

When I speak of S+N/N, this is to mean that extraneous detail (fables
of mosquitoes, large cars and even larger blimps) only adds noise.

Skip the "extraordinary," stop the fables, and simply state your case.
When you remove all this noise, you may discover you are not writing
about a quantum system at all, but numbers without meaning. A simple
test: what changes its quantum state at 3.5MHz? Is it sub-atomic,
atomic, or molecular?

Richard: Why a "white board"? has a special meaning? - You are
saying Cecil it is as Dr. House? - Really nice car your RX-7, I envy
you! - My London friend is "missing2 I owe you some answers :(

Dr. House refuses to let students write on his white board.

I've driven RXs for 28 years: a 1978 and a 1990 GTU.

London is a nice place to be missing in. I've spent time near
Vauxhall bridge in Westminster.

73's
Richard Clark, KB7QHC

what happens to reflected energy ?
 

On Jul 5, 1:26*am, Keith Dysart wrote:
On Jul 1, 8:53*am, K1TTT wrote:



On Jul 1, 12:37*pm, Cecil Moore wrote:

On Jun 30, 11:29*am, Keith Dysart wrote:

Check the a0 coefficient in the Fourier transform. This represents
the DC component of the signal.

And the result is zero EM waves, either forward or reflected, and your
argument falls apart.

Without this, how would you deal with a signal such as
* V(t) = 10 + 2 cos(3t)

If the cosine term is zero, there are zero EM waves, either forward or
reflected, and your argument falls apart.

Incidentally, V(t) = 10, is a perfect way to prove that energy and the
time derivitive of energy are not the same thing and your argument
falls apart.

Alternatively, one can use the standard trick for dealing with
non-repetitive waveforms: choose an arbitrary period. 24 hours
would probably be suitable for these examples and transform from
there. Still, you will have zero frequency component to deal
with, but there will be some at higher frequencies (if you
choose your function to make it so).

Windowing doesn't generate EM waves where none exist in reality and
your argument falls apart.
--
73, Cecil, w5dxp.com

a better argument is that a constant voltage produces a constant
electric field everywhere, since the field is not varying in time or
space there is no time or space derivative to create a magnetic field
so there can be no propagating em wave. *you could do the same with
zero or constant current producing a constant magnetic field.

The same question for you...

With an infinitely long transmission line excited by a step function,
is there an EM wave propagating down the line?

If not, what is it that is propagating down the line? Especially at
the leading edge?

essentially the dc case IS unique in that you must wait forever for it
to reach sinusoidal steady state since the lowest frequency component
is 0hz

You have used similar phrases before. Are you suggesting that an
open circuited transmission line excited with a step function takes
infinitely long to read steady state?

...Keith

'it depends'... in the special case you have concocted where the
signal source has no reflections it only takes one round trip. this
case is very misleading if you try to extend it to cover other cases.
in general it takes infinitely long and you must account for the
infinite series of reflections. that is why the approximations used
to come up with the sinusoidal steady state solution is so useful, and
exactly why it can not be applied to steps and square waves and other
non sinusoidal constant sources.


and in your infinite line example it never reaches steady state so the
step wave propagates forever.

what happens to reflected energy ?
 

On Jul 5, 1:58*am, Keith Dysart wrote:
On Jul 1, 10:20*am, Cecil Moore wrote:



On Jun 30, 11:30*am, Keith Dysart wrote:

But you are NOT adding up the energy flows - you are adding up the
power.

Ummm. Energy flow is power. Joules/s!

If it helps, any place I have written 'power', please replace with
'energy flow'.

One too many words - what I meant to say is that you are not adding up
the energy - you are adding up the power. There is no such thing as
conservation of energy flow. That is proved by your own graphs. There
are times when the energy flow is destroyed. There are other points on
your power graphs where energy flow is created.

There is no conflict with conserving flows, ...

The conflict is that conservation of flows doesn't exist. Keith, you
need to go back to college. There is no such thing as conservation of
energy flow so your argument falls apart. When one looks up
"conservation" in a physics book one finds:

conservation of energy principle
conservation of mass-energy
conservation of mechanical energy
conservation of momentum principle

There is NO conservation of energy flow or conservation of power.
Until you give up on that ridiculous concept, we don't have much to
discuss except your religion.

One example you should be familiar with is Kirchoffs Current Law;
it tells you that sum of the FLOWs must equal 0 based on the
Conservation of Charge law. Recall that current is charge per
unit time.

For a more general treatment look up 'Continuity equation' in
Wikidedia where you will find "A continuity equation in physics is a
differential equation that describes the transport of some kind of
conserved quantity. Since mass, energy, momentum, electric charge
and other natural quantities are conserved, a vast variety of
physics may be described with continuity equations.".

Welcome to a new tool for analysis.



What happens when energy = 1 joule, and de/dt = 0 watts. This happens
all the time during an RF cycle so you are not using actual energy
flows. You are using power which goes to zero even when maximum energy
is still present.

Yes, indeed. That is a fundamental possibility and occurs on
transmission lines with infinite VSWR.

If power goes to zero, power has been destroyed. Therefore, there is
no conservation of power principle. Anything that can go to zero, i.e.
can disappear, cannot be conserved.

Power is the time derivitive of energy. They are related
but definitely not one-to-one.

Well, that shoots your argument down. If power and energy do not have
a one-to-one correspondence, then you cannot use the conservation of
energy principle to prove that power is conserved and your argument
falls apart. You must then product a conservation of power principle,
something that every physics professor has warned us doesn't exist.

I can provide any number of references to support the conservation of
energy principle. Please provide just one bona fide reference that
supports your conservation of energy flow (power) principle.

See above, though it seems the common term is Continuity equation.

This is quite incorrect. Energy flows must balance, otherwise energy
is being created or destroyed to sustain a difference in flow.

Good grief! Any physicist knows that is false. Any number of examples
prove that is false.

Energy flows must balance as well. Otherwise,
energy is coming from nowhere to sustain the flow.

Given a black box with an input and output. Measurements of the power
flow vector indicates that the magnitude of each power flow vector is
50 watts and both vectors are pointing inside the black box. How can
the instantaneous energy flows possibly balance?

Inside the box are some elements whose stored energy is increasing
at the same rate.

Instead, think that at every instant, the energy flow between the
entities in the experiment must balance.

You are contradicting yourself. Assume the capacitor *IS* the system
inside a black box. The instantaneous energy flow does NOT balance.

Expand your thinking a bit. Energy is being stored in the capacitor.
You do need to account for this. It is just another flow to track.

It is the
total energy within the system that is conserved, just as it is
the total of the flows of energy between the entities within the
system that must be conserved.

You have it half right. Energy must be conserved. Energy flow is not
conserved.

See above.

Put more strictly: The sum of all the energy flows in to all of
the entities within the system must equal the energy flow in to
the system.

Please see the black box experiment above and balance the energy flow.
Please produce a reference for the conservation of power principle.

See above.

...Keith

'normally' black boxes are just that, opaque elements that you can not
measure an internal state with. when you specify a box or something
generic with a couple of ports any good engineer will assume that you
know NOTHING about what is inside the box, and that you don't care.
those type of simplifications are common in engineering methods in
order to simplify problems down to the things that you are really
interested in... normally BY DEFINITION you don't know and don't care
about what is inside 'the box'. so your statement that you know the
energy stored in the box is a function of instantaneous flows in and
out is non-sequitar, we engineers just don't care and would never try
to do a balance like that. if you want to study the energy flow in
and out of a box AND the storage of it in the box then provide the
circuit for the box and study it properly.

for instance, take your infinitely long transmission line. as an
engineer my first action is to reduce that line to a resistor that has
a value equal to the characteristic impedance of the line. i can use
that equivalent resistor for all calculations for EVERYTHING ELSE in
the circuit, but NOT for the internal state of the replacement box....
for obviously if you look in the box and find a resistor dissipating
all the power you put into it as heat that will be much different from
looking in the box and seeing an infinite transmission line with all
that energy propagating forever as an em wave.

what happens to reflected energy ?
 

On Jul 5, 8:12*am, "Szczepan Bialek" wrote:
"K1TTT" ...
On Jul 4, 4:19 pm, "Szczepan Bialek" wrote:



In electromagnetics Maxwell and Heaveside are the experts. Available on
line.
unfortunately you have to learn modern em to know what writings of

maxwell and heaveside to bother believing... they both went through
learning periods before they came to the final transverse wave
formulations. *if you read their earlier works you will be mislead
because they were still learning and following dead end paths like
aether theory and fluid analogies.

Maxwell's aether was as perfect solid with the molecular vortices. The
magnetic field was the sum of the molecular.
The Faraday effect was explained. Transverse waves possible. But in solid
possible are also the longitudinal.
Which of them are in reality decide experiments.

Heaviside modified Maxwell' model. His aether is also motionless but withot
the molecular vortices:http://en.wikisource.org/wiki/Electr..._moving_charge


if that is all the further you have read then you have much to learn.
at the very beginning they are conjecturing about the possibility of
infinite vs finite propagation velocity, so obviously they have not
made the critical measurements yet to refine the equations to the
proper ones and eliminate all the possible aetheric solutions.

what happens to reflected energy ?
 

On Jul 4, 8:08*pm, Keith Dysart wrote:
The system I have in mind has ports through which energy can flow in
or out of the system and components inside the system which can
store energy. For such a system, the energy flowing in to ports
of the system minus the energy flowing out of ports *must
equal the increase in energy being stored in the system.

This must be true at all times, or energy is being created or
destroyed; a bit of a no-no.

But you are not tracking energy - you are tracking power. As Roy has
said, there is no requirement that instantaneous power must balance.
Where are the stored energy terms in any of your instantaneous power
equations? How do you handle the difference in dimensions between
energy and power? The only condition for which NET power must balance
is during a time interval in which there is zero NET stored power,
e.g. during one cycle.

I have rev'ed my zero interference article to include the following
statement:

"Over a time period of many cycles, e.g. one second at MHz
frequencies, the net average energy and the net average power are
related by joules/second. Thus, if certain conditions are met, net
average power can be used to track the net average energy flow based
on the conservation of energy principle. However, at time intervals of
less than one cycle, as exists for instantaneous power, power cannot
be used to track energy because energy is often stored in a reactance,
is not moving at that instant, and is therefore technically not power.
In fact, unlike energy, power often appears and disappears. There are
special cases where average power in joules/second can be used to
track average energy in joules but instantaneous power is not one of
those special cases."
--
73, Cecil, w5dxp.com

what happens to reflected energy ?
 

On Jul 4, 8:24*pm, Keith Dysart wrote:

From Wikipedia, I have just learned that the concept I am
attempting to describe is known as a "Continuity equation".

In all your previous equations, you have presented only the first term
and completely ignored the second (delta-dot-v) term of the equation
which is required for balance. When you add the proper term, i.e. you
track and account for all of the energy, your energy equation will
balance - as I told you days ago.

So how do you characterize a slow square wave? Say one that is 0V for
one year, then 10V for a year, then 0, then...

The same way I characterize, "How many angels can dance on the head of
a pin?" The length of time makes absolutely no difference to the
concept involved. The above conditions do not match the DC steady-
state conditions of your earlier example.

With an infinitely long transmission line excited by a step function,
is there an EM wave propagating down the line?

Yes, there is an EM wave at the leading edge. Electrons cannot move at
the speed of light. But it is impossible to window such an example in
a valid manner because windowing creates other EM waves where none
exist in your example. There is no trailing edge in your example yet
windowing would necessarily create a trailing edge. Since an
infinitely long transmission line is impossible, we are back to the
"angels on the head of a pin" problem. In any region of the example
where steady-state DC conditions exist, EM waves have ceased to exist.
That's what happens when you make the line a fixed length and
terminate it at that point. Anywhere DC steady-state conditions exist,
your DC forward and reflected wave analysis falls apart.
--
73, Cecil, w5dxp.com

what happens to reflected energy ?
 

On Jul 4, 8:26*pm, Keith Dysart wrote:
Are you suggesting that an
open circuited transmission line excited with a step function takes
infinitely long to read steady state?

Your infinitely long open-circuited transmission line example
certainly takes infinitely long to reach steady-state so the leading-
edge EM wave continues forever with zero reflected EM waves and your
argument involving reflected waves falls apart.

Your finite open-circuited transmission line example reaches DC steady-
state where EM waves cease to exist so your argument involving forward
and reflected waves falls apart.
--
73, Cecil, w5dxp.com

what happens to reflected energy ?
 

On Jul 4, 8:58*pm, Keith Dysart wrote:
Expand your thinking a bit. Energy is being stored in the capacitor.
You do need to account for this. It is just another flow to track.

I don't need to track it. I am not the one who is arguing that
instantaneous power is conserved. I have said all along that your
instantaneous power equations were not tracking all the energy. It is
*you* who have not been tracking the energy stored in the capacitor.
When you do that in a valid way, you will discover that the energy
does balance but the instantaneous power still does NOT balance, nor
is it required to balance. IT IS ENERGY THAT IS CONSERVED, NOT POWER!
Please note that the 'Continuity equation' discussion does *NOT* list
power as one of the conserved quantities.
--
73, Cecil, w5dxp.com

what happens to reflected energy ?
 

On Jul 5, 1:16*pm, Cecil Moore wrote:
On Jul 4, 8:26*pm, Keith Dysart wrote:

Are you suggesting that an
open circuited transmission line excited with a step function takes
infinitely long to read steady state?

Your infinitely long open-circuited transmission line example
certainly takes infinitely long to reach steady-state so the leading-
edge EM wave continues forever with zero reflected EM waves and your
argument involving reflected waves falls apart.

Your finite open-circuited transmission line example reaches DC steady-
state where EM waves cease to exist so your argument involving forward
and reflected waves falls apart.
--
73, Cecil, w5dxp.com

'dc steady state' is an oxymoron...