On Apr 18, 5:01 pm, Cecil Moore wrote:
On Apr 18, 11:54 am, Keith Dysart wrote:

It is unfortunate, but you are back where you started;
choosing not to learn. Opportunity squandered.

And BTW, so are you. You ignored my earlier posting which poked holes
in your model so I am going to repeat it until you respond to it. We
know exactly what happens to the reflected energy when a signal
generator equipped with a circulator and load are used in the
following experiment.

Well, we shall see. Let us call this Experiment A.

100W SGCL----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100 watts reflected. The
source sources 100 watts and the circulator resistor dissipates 100
watts which is all of the reflected power.

True, except for one quibble which I will detail near the end of this
post.

Let us call this next one Experiment B.

Keith's 70.7V/50 ohm source----50 ohm 1/4WL stub----short

A Bird wattmeter reads 100 watts forward and 100w reflected. The
current in the source is zero. The source is not only not sourcing any
forward power, it is also not sinking any reflected power. So much for
Keith's source sinking all the reflected power because it's source
impedance is equal to 50 ohms, the Z0 of the transmission line.

I have never claimed that the source in any way sank the 'reflected
power'.
I have stated that there is no re-reflection of the reflected wave at
the
source. Since the source is matched to the line, the reflection
coefficient is 0 and the wave just .... Well it must go into the
source
since tau is one. But at least it is not reflected when rho is zero.

As you observe for Experiment B, the current is zero so as you
say "The source is not only not sourcing any forward power, it is
also not sinking any reflected power."

Of course the current is also zero at the same point for
Experiment A, so there as well, the source is not only not sourcing
any forward power, it is also not sinking any reflected power.

A bit more analysis for Experiment A yields some more questions.
Terminate the line with a 50 Ohm resistor. The source is now
providing power to the line, there is no reflection on the line and
the circulator dissipates nothing.
Remove the resistor. The reflection returns. The circulator once
again dissipates 100 W. But as you said, in this condition,
"The source is not only not sourcing any forward power, it is also
not sinking any reflected power." So where did that 100 W being
dissipated in the circulator come from?

I suggest a further extension to both Experiment A and
Experiment B. Replace the 1/4 WL stub with a 1 and 1/4 WL
stub. Now, at each 1/4 WL along the line coming back from
the load, no energy is flowing because either the current is
0 or the voltage is 0. So this absence of energy flow happens
not just at the source but repeatedly along the line. This
makes it difficult to accomodate the thought that the
forward or reflected travelling waves are transporting energy
along the line (at least at the quarter wave points).

Now back to the quibble. You said: "The source sources 100 watts
and the circulator resistor dissipates 100 watts which is all of the
reflected power."

It would be more precise to say "The source sources 100 watts
and the circulator resistor dissipates 100 watts which is numerically
equal to the reflected power." I contend that it is this "numerical
equality" that has led many astray into believing that the
circulator is dissipating the "reflected power". But as we have seen,
no energy crosses the 0 current node into the generator so the
"reflected power" can not make it to the circulator (or the source
resistance, if the generator happens to have one).

Please don't ignore this posting like you did last time.

As requested.

....Keith