On Jun 25, 9:00*am, Cecil Moore wrote:
On Jun 25, 2:13*am, lu6etj wrote:

In a TL, instead, total destructive interference in one point would
mean energy stop flowing from that point forwards (is it OK say
"forwards"?) and reverse its flow direction doubling his value, is it
OK?.

In our ham transmission line systems, the goal is to accomplish total
destructive interference toward the source, i.e. zero reflected energy
incident upon the source. So let's talk about destructive interference
toward the source and constructive interference toward the load.

You name it "redistribution" too, not reflection.

By definition, reflection is something that happens to a single wave.
By definition, superposition involves two or more waves. The
redistribution that I am talking about can include both reflection and
superposition if both are present. Depending upon the system
configuration, both may be present, both may be absent, or one exist
without the other.

Well, my
question was how we can set (devise) an experiment to get such
behaviour in a TL?

I've presented it before and it is a simple Z0-match involving a 1/4WL
matching section.

50w-----50 ohm------+------1/4WL 300 ohm------1800 ohm load

On the source side, rho at '+' is 0.7143

Using a TDR, we can verify that there is indeed a reflection from the
50/300 ohm impedance discontinuity. What happens to that reflection
during steady-state?

What happens to Vfor1(rho) = 50v(0.7143) = 35.7v?

Using superposition, when you add Vrev2(tau) to Vfor1(rho) you get
zero.
With zero voltage comes 0 energy transfer.

For further learning, do not just examine steady state, but also
examine
how it gets to steady state. Using a lattice diagram, examine what
happens as the first reflection and then each re-reflection arrives at
'+'. Determine how Vrev2(tau) slowly builds to equal Vrev1 and cancels
it, using the simple addition of superposition. While this process is
occurring, there is a Vrev1 which decreases after each round trip in
the second line section.

This is all done with simple addition. No need for products and square
roots.

For further marks, decide whether you should think of Vrev2 as an
infinite sum of reverse waves or is it okay to think of it as one sum
that slowly accumulates.
Which is it really?

Same question for Vfor2.

What happens to Pfor1(rho^2) = 50w(0.51) = 25.5w?

Once you have computed total Vrev1 using simple superposition, it is
easy to compute that the "reverse power", Prev1, is 0.

Do you really need rho^2 to understand what goes on in a transmission
line?

....Keith

On Jun 25, 7:07*pm, Keith Dysart wrote:
Using superposition, when you add Vrev2(tau) to Vfor1(rho) you get
zero. With zero voltage comes 0 energy transfer.

Completing your above sentence: With zero voltage comes 0 energy
transfer *in the direction of travel of the original waves that were
superposed*. Assuming that you believe in the conservation of energy
principle, what happened to the energy in the two component voltage
waves necessary for their existence before they cancel each other? If
they didn't contain any energy, they would be zero but we know they
are not zero, i.e. they are 35.7 volts each. That original wave energy
is redistributed and *transfered* in the opposite direction, the only
other direction available in a transmission line.

One cannot argue with a forked tongue that the superposed waves never
existed in the first place because that would violate the laws of
physics and superposition.

Do you really need rho^2 to understand what goes on in a transmission
line?

Not using rho^2 is why you are so confused. If you actually cared
where the energy goes, you would be forced to use rho^2 or at least
multiply the superposition component voltages and currents to obtain
the power in the superposition component wavefronts.

In the earlier example, the impedance discontinuity has a physical
voltage reflection coefficient of 0.7143 and a physical power
reflection coefficient of 0.51. If you consider the steady-state power
conditions, you will calculate a virtual power reflection coefficient
of 0.0 and a virtual voltage reflection coefficient of 0.0. Which
reflection coefficient is correct? Obviously, physical trumps virtual
every time.

The 50v source voltage reflected at the 0.7143 reflection coefficient
is 35.7 volts and it exists in a 50 ohm environment. Simple math
yields the power = (35.7)^2/50 = 25.5 watts. Where did the energy in
that 25.5 watt EM wave go? One can obtain the same value by
calculating the current: 1a(0.7143) = 0.7143. Power = 35.7(0.7143) =
25.5 watts.

So you can get by without using rho^2 but to determine where the
energy is going, one needs to at least multiply the EM traveling-wave
voltage by the EM traveling-wave current (or calculate the ExH
Poynting vectors).

In fact, this would be a good application for your instantaneous power
calculations. Where is the energy going that is in the instantaneous
power being reflected by the impedance discontinuity?
--
73, Cecil, w5dxp.com

On Jun 26, 9:49*am, Cecil Moore wrote:
On Jun 25, 7:07*pm, Keith Dysart wrote:

Using superposition, when you add Vrev2(tau) to Vfor1(rho) you get
zero. With zero voltage comes 0 energy transfer.

Completing your above sentence: With zero voltage comes 0 energy
transfer *in the direction of travel of the original waves that were
superposed*. Assuming that you believe in the conservation of energy
principle, what happened to the energy in the two component voltage
waves necessary for their existence before they cancel each other?

The fundamental question is: "did they have energy?"

Let us express this as a hypothesis:

Hypothesis 1: The component voltage waves have energy.

Then it should follow that we can trace this energy and discover
where it goes.

At least three examples have been proposed where the energy can
not be properly traced:

Example 1: Step function applied to a transmission line. After the
line settles, a forward and reflected voltage wave
continue on the line but no energy is being transferred.
Example 2: On a line with infinite VSWR no energy crosses a
voltage minimum or maximum.
Example 3: With the 1/8 wavelength line described in
http://www.w5dxp.com/nointfr.htm the energy can not be
properly accounted for on a moment by moment basis.

Only one counter-example was needed to disprove the hypothesis,
three have been found. There may be more.

Hypothesis is disproved.

No matter how many examples are found that support the hypothesis,
the hypothesis is still disproved.

....Keith

On Jun 27, 2:23*pm, Keith Dysart wrote:
Example 1: Step function applied to a transmission line. After the
* * * * * *line settles, a forward and reflected voltage wave
* * * * * *continue on the line but no energy is being transferred.

As far as I am concerned, if Maxwell's equations don't work on an
example, it might as well be ignored. There is nothing during DC
steady-state that allows Maxwell's equations to work because there are
no EM waves during DC steady-state. Why don't you already know that?

I can take your approach and do you one better. Please prove that you
exist. If you cannot prove that you exist, then nothing you say is of
any consequence. See, I can do it also.

Example 2: On a line with infinite VSWR no energy crosses a
* * * * * *voltage minimum or maximum.

Completely false assumption. You are back to asserting that since the
north-bound traffic equals the south-bound traffic on the Golden Gate
Bridge that there is no traffic and no bridge maintenance is required.
When are you going to give up on that irrational wet dream of yours?
No *NET* energy crosses at a voltage zero or current zero point. That
doesn't make the north-bound energy equal to zero and doesn't make the
south-bound energy equal to zero. It just makes them equal. Just
because there is no NET traffic flow on the Golden Gate Bridge doesn't
mean there is zero traffic flow in both directions. Please stop
clowning around with such absurb notions.

Example 3: With the 1/8 wavelength line described in
* * * * * *http://www.w5dxp.com/nointfr.htmthe energy can not be
* * * * * *properly accounted for on a moment by moment basis..

There is no conservation of power principle. If you would track the RF
joules and the conversion of RF joules to heat instead of the joules/
second, everything would become clear to you. As it is, you are
laboring under some serious misconceptions about the laws of physics.
Power simply doesn't balance within a single cycle - because it
doesn't have to - because there is no conservation of power principle.

People who don't learn from their mistakes are doomed to commit the
same mistakes over and over. Keith, you seem to be all output and no
input. Please enable your input channels for a change.
--
73, Cecil, w5dxp.com

On Jun 27, 4:27*pm, Cecil Moore wrote:
On Jun 27, 2:23*pm, Keith Dysart wrote:

Example 1: Step function applied to a transmission line. After the
* * * * * *line settles, a forward and reflected voltage wave
* * * * * *continue on the line but no energy is being transferred.

As far as I am concerned, if Maxwell's equations don't work on an
example, it might as well be ignored. There is nothing during DC
steady-state that allows Maxwell's equations to work because there are
no EM waves during DC steady-state. Why don't you already know that?

I always thought that Maxwell's equations were more complete than that
and worked all the way down to DC. Two of them do not even include
time
and nothing says that a derivative with respect to time can't be 0.

I can take your approach and do you one better. Please prove that you
exist. If you cannot prove that you exist, then nothing you say is of
any consequence. See, I can do it also.

From the above, you have proved that I exist. Thank you.

Example 2: On a line with infinite VSWR no energy crosses a
* * * * * *voltage minimum or maximum.

Completely false assumption. You are back to asserting that since the
north-bound traffic equals the south-bound traffic on the Golden Gate
Bridge that there is no traffic and no bridge maintenance is required.
When are you going to give up on that irrational wet dream of yours?
No *NET* energy crosses at a voltage zero or current zero point. That
doesn't make the north-bound energy equal to zero and doesn't make the
south-bound energy equal to zero. It just makes them equal. Just
because there is no NET traffic flow on the Golden Gate Bridge doesn't
mean there is zero traffic flow in both directions. Please stop
clowning around with such absurb notions.

I suppose, but then you have to give up on P(t)=V(t)*I(t), generally
considered to be a rather fundamental equation.

Example 3: With the 1/8 wavelength line described in
* * * * * *http://www.w5dxp.com/nointfr.htmtheenergy can not be
* * * * * *properly accounted for on a moment by moment basis.

There is no conservation of power principle.

There is no mention of power above; simply energy.

Are you saying that conservation of energy only applies some of
the time?

If you would track the RF
joules and the conversion of RF joules to heat instead of the joules/
second, everything would become clear to you. As it is, you are
laboring under some serious misconceptions about the laws of physics.
Power simply doesn't balance within a single cycle - because it
doesn't have to - because there is no conservation of power principle.

In your example, the RF energy does seem to disappear and re-appear,
when tracked on a moment by moment basis.

People who don't learn from their mistakes are doomed to commit the
same mistakes over and over. Keith, you seem to be all output and no
input. Please enable your input channels for a change.

Well, it would help if you could actually find and articulate a flaw
in http://sites.google.com/site/keithdysart/radio6.

....Keith

On Jun 27, 6:59*pm, Keith Dysart wrote:
From the above, you have proved that I exist. Thank you.

Nope, I believe you are only a figment of my imagination. Please prove
that you actually exist.

I suppose, but then you have to give up on P(t)=V(t)*I(t), generally
considered to be a rather fundamental equation.

I have absolutely no problem with giving up on the conservation of
power principle in which no rational technical person can possibly
believe.

Are you saying that conservation of energy only applies some of
the time?

No, I am saying that if you cannot balance the energy equation at all
times, you have made a mistake. You are not tracking joules. You are
attempting to track watts which can appear and disappear at any time.
The only condition where watts can be tracked is over an integer
multiple of complete cycles. That's why watts can be tracked when the
frequency is in the MHz. Trying to track instantaneous watts within a
fraction of a cycle is a moronic attempt at power superposition, a no-
no that we all learned in EE101.

In your example, the RF energy does seem to disappear and re-appear,
when tracked on a moment by moment basis.

No, the power can disappear and re-appear but the energy cannot. You
have not even come close to tracking the energy.

Well, it would help if you could actually find and articulate a flaw
inhttp://sites.google.com/site/keithdysart/radio6.

The flaw is your belief in a conservation of power principle that
doesn't exist. Instantaneous power is not required to obey any
conservation principle. What you are doing on that web page is
attempting to superpose powers apparently without a clue.

Superposition of power is a no-no. The power density equation allows
us to accomplish the addition of *average* powers taking interference
into effect. I know of no such mathematical equations for
instantaneous power and your instantaneous power superposition
technique is obviously invalid.
--
73, Cecil, w5dxp.com

On Jun 27, 9:48*pm, Cecil Moore wrote:
On Jun 27, 6:59*pm, Keith Dysart wrote:
I suppose, but then you have to give up on P(t)=V(t)*I(t), generally
considered to be a rather fundamental equation.

I have absolutely no problem with giving up on the conservation of
power principle in which no rational technical person can possibly
believe.

There again, a non-sequitor non-answer.

Do you reject P(t)=V(t)*I(t) ?

Are you saying that conservation of energy only applies some of
the time?

No, I am saying that if you cannot balance the energy equation at all
times, you have made a mistake.

I agree completely. And my analysis does successfully track all the
energy at all times.

And after averaging, it even agrees with your analysis.

Methinks that you are perturbed that it demonstrates that your
analysis
does not track all the energy all the time, but only succeeds with
averages.

....Keith

On Jun 27, 11:59*pm, Keith Dysart wrote:
On Jun 27, 4:27*pm, Cecil Moore wrote:

On Jun 27, 2:23*pm, Keith Dysart wrote:

Example 1: Step function applied to a transmission line. After the
* * * * * *line settles, a forward and reflected voltage wave
* * * * * *continue on the line but no energy is being transferred.

As far as I am concerned, if Maxwell's equations don't work on an
example, it might as well be ignored. There is nothing during DC
steady-state that allows Maxwell's equations to work because there are
no EM waves during DC steady-state. Why don't you already know that?

I always thought that Maxwell's equations were more complete than that
and worked all the way down to DC. Two of them do not even include
time
and nothing says that a derivative with respect to time can't be 0.


of course they do constant electric field and constant magnetic fields
work just fine and go out to infinity in the dc steady state case.
this of course means there can be no moving electrons, therefor no
current, no d/dt terms, etc... which means no waves.


I can take your approach and do you one better. Please prove that you
exist. If you cannot prove that you exist, then nothing you say is of
any consequence. See, I can do it also.

From the above, you have proved that I exist. Thank you.

i would debate the existence of a vacuum.


Example 2: On a line with infinite VSWR no energy crosses a
* * * * * *voltage minimum or maximum.

Completely false assumption. You are back to asserting that since the
north-bound traffic equals the south-bound traffic on the Golden Gate
Bridge that there is no traffic and no bridge maintenance is required.
When are you going to give up on that irrational wet dream of yours?
No *NET* energy crosses at a voltage zero or current zero point. That
doesn't make the north-bound energy equal to zero and doesn't make the
south-bound energy equal to zero. It just makes them equal. Just
because there is no NET traffic flow on the Golden Gate Bridge doesn't
mean there is zero traffic flow in both directions. Please stop
clowning around with such absurb notions.

I suppose, but then you have to give up on P(t)=V(t)*I(t), generally
considered to be a rather fundamental equation.

very fundamental, and very restricted. only good for one point in
space at one time, and for one pair of voltage and current
measurements... can not be applied to separate waves that are
superimposed, only to the final total voltage and current at the
measurement point at that instant.



Example 3: With the 1/8 wavelength line described in
* * * * * *http://www.w5dxp.com/nointfr.htmtheenergycan not be
* * * * * *properly accounted for on a moment by moment basis.

There is no conservation of power principle.

There is no mention of power above; simply energy.

Are you saying that conservation of energy only applies some of
the time?

If you would track the RF
joules and the conversion of RF joules to heat instead of the joules/
second, everything would become clear to you. As it is, you are
laboring under some serious misconceptions about the laws of physics.
Power simply doesn't balance within a single cycle - because it
doesn't have to - because there is no conservation of power principle.

In your example, the RF energy does seem to disappear and re-appear,
when tracked on a moment by moment basis.


when doing conservation of energy you must include the WHOLE system!
it doesn't work on one section of a transmission line any more than it
works for the infamous undergraduate teaser:

take a refrigerator, put it in a perfectly insulated room, and then
open the doors... what happens to the temperature in the room?


People who don't learn from their mistakes are doomed to commit the
same mistakes over and over. Keith, you seem to be all output and no
input. Please enable your input channels for a change.

Well, it would help if you could actually find and articulate a flaw
inhttp://sites.google.com/site/keithdysart/radio6.

...Keith

that site is rather worthless... you say Vs can be used to get the
time reference for the other signals, but time is a variable, as is
space. you seem to have a snapshot of a bunch of sine waves on an
angular scale, but is that scale time or distance?

On Jun 28, 5:11 pm, K1TTT wrote:
On Jun 27, 11:59 pm, Keith Dysart wrote:
I suppose, but then you have to give up on P(t)=V(t)*I(t), generally
considered to be a rather fundamental equation.

very fundamental, and very restricted. only good for one point in
space at one time, and for one pair of voltage and current
measurements... can not be applied to separate waves that are
superimposed, only to the final total voltage and current at the
measurement point at that instant.

True, but others reject it completely.

In your example, the RF energy does seem to disappear and re-appear,
when tracked on a moment by moment basis.

when doing conservation of energy you must include the WHOLE system!
it doesn't work on one section of a transmission line any more than it
works for the infamous undergraduate teaser:

take a refrigerator, put it in a perfectly insulated room, and then
open the doors... what happens to the temperature in the room?

The teaser is amusing, but hardly relevant. In my example, all of
the energy is tracked. Or, I invite you to point out that which was
overlooked. Cecil has not found any and would rather prattle on about
the difference between energy and power than actually understand.

Well, it would help if you could actually find and articulate a flaw
inhttp://sites.google.com/site/keithdysart/radio6.

...Keith

that site is rather worthless... you say Vs can be used to get the
time reference for the other signals, but time is a variable, as is
space. you seem to have a snapshot of a bunch of sine waves on an
angular scale, but is that scale time or distance?

Time, of course. I agree, though, it is not as clear as it could
have been. It helps a bit if you look at Cecil’s schematic.

Still, it is complicated and will probably take some effort to
understand.

It would probably be better to start with the step wave example
offered previously in another post and copied below for
convenience:

example
I am not sure where you think there is an error. Perhaps you can
point them out in the following example:
Generator:
- 100V step in to an open circuit
- 50 ohm source impedance
Line:
- 50 ohm
- open circuit
Generator is commanded to produce a step.
This will produce 50 V and 1 A at the line input which will
propagate down the line.
The open end of the line has a reflection co-efficient of 1.0.
Just before the 50 V step reaches the end of the line, the
whole line will be at 50 V and 1 A will be flowing everywhere.
The 50 V step hits the end and is reflected, producing a 50 V
step (on top of the 50V already there) which propagates back
to the generator. In front of the 50 V step, the current is
still 1 A (which provides the charge necessary to produce
the reverse propagating 50 V step. Behind the step, the
current is 0.
When the reverse 50 V step (which is actually a step from
50V to 100V) reaches the generator, the source impedance
matches the line impedance so there is no further reflection.
The line state is now 100V and 0A all along its length.
The settling time was one round-trip.
The generator is still producing the step, so the forward
step voltage wave is still 'flowing' and being reflected so
there is still a reflected step voltage wave, each of 50 V.
Since the generator open circuit voltage is 100 V and the
line voltage is now 100 V, current is no longer flowing
from the generator to the line.
Does this agree with your understanding?
/example

....Keith

On Jun 27, 11:59*pm, Keith Dysart wrote:
On Jun 27, 4:27*pm, Cecil Moore wrote:

On Jun 27, 2:23*pm, Keith Dysart wrote:

Example 1: Step function applied to a transmission line. After the
* * * * * *line settles, a forward and reflected voltage wave
* * * * * *continue on the line but no energy is being transferred.

As far as I am concerned, if Maxwell's equations don't work on an
example, it might as well be ignored. There is nothing during DC
steady-state that allows Maxwell's equations to work because there are
no EM waves during DC steady-state. Why don't you already know that?

I always thought that Maxwell's equations were more complete than that
and worked all the way down to DC. Two of them do not even include
time
and nothing says that a derivative with respect to time can't be 0.


of course they do constant electric field and constant magnetic fields
work just fine and go out to infinity in the dc steady state case.
this of course means there can be no moving electrons, therefor no
current, no d/dt terms, etc... which means no waves.


I can take your approach and do you one better. Please prove that you
exist. If you cannot prove that you exist, then nothing you say is of
any consequence. See, I can do it also.

From the above, you have proved that I exist. Thank you.

i would debate the existence of a vacuum.


Example 2: On a line with infinite VSWR no energy crosses a
* * * * * *voltage minimum or maximum.

Completely false assumption. You are back to asserting that since the
north-bound traffic equals the south-bound traffic on the Golden Gate
Bridge that there is no traffic and no bridge maintenance is required.
When are you going to give up on that irrational wet dream of yours?
No *NET* energy crosses at a voltage zero or current zero point. That
doesn't make the north-bound energy equal to zero and doesn't make the
south-bound energy equal to zero. It just makes them equal. Just
because there is no NET traffic flow on the Golden Gate Bridge doesn't
mean there is zero traffic flow in both directions. Please stop
clowning around with such absurb notions.

I suppose, but then you have to give up on P(t)=V(t)*I(t), generally
considered to be a rather fundamental equation.

very fundamental, and very restricted. only good for one point in
space at one time, and for one pair of voltage and current
measurements... can not be applied to separate waves that are
superimposed, only to the final total voltage and current at the
measurement point at that instant.



Example 3: With the 1/8 wavelength line described in
* * * * * *http://www.w5dxp.com/nointfr.htmtheenergycan not be
* * * * * *properly accounted for on a moment by moment basis.

There is no conservation of power principle.

There is no mention of power above; simply energy.

Are you saying that conservation of energy only applies some of
the time?

If you would track the RF
joules and the conversion of RF joules to heat instead of the joules/
second, everything would become clear to you. As it is, you are
laboring under some serious misconceptions about the laws of physics.
Power simply doesn't balance within a single cycle - because it
doesn't have to - because there is no conservation of power principle.

In your example, the RF energy does seem to disappear and re-appear,
when tracked on a moment by moment basis.


when doing conservation of energy you must include the WHOLE system!
it doesn't work on one section of a transmission line any more than it
works for the infamous undergraduate teaser:

take a refrigerator, put it in a perfectly insulated room, and then
open the doors... what happens to the temperature in the room?


People who don't learn from their mistakes are doomed to commit the
same mistakes over and over. Keith, you seem to be all output and no
input. Please enable your input channels for a change.

Well, it would help if you could actually find and articulate a flaw
inhttp://sites.google.com/site/keithdysart/radio6.

...Keith

that site is rather worthless... you say Vs can be used to get the
time reference for the other signals, but time is a variable, as is
space. you seem to have a snapshot of a bunch of sine waves on an
angular scale, but is that scale time or distance?