On May 27, 4:15*pm, walt wrote:
And referring to a statement Dysart made concerning plate resistance,
Rp, it must be understood that in Class AB, B and C amplifiers, Rp is
NOT the source resistance.

You left Class A out of the list. Does this mean that Rp is the source
resistance for a Class A amplifier?

....Keith

Keith Dysart wrote in news:7974e65c-6e3a-442b-
:


You left Class A out of the list. Does this mean that Rp is the source
resistance for a Class A amplifier?

Keith,

Assertions have been made about the Thevenin equivalent source impedance
(Zs) of an RF PA. In the discussions over the years, some people have
imposed some qualifications (eg classes, tuned / untuned etc).

Zs can be measured by a number of methods. It is interesting to note that
in many of the discussions on the 'net on this topic, more focus is given
to dismissing the experiment design for experiments that produce
unfavourable results to some, than questioning the proposition that Zs is
50+j0 or thereabouts.

Whilst Walt has documented a quite rigourous experiment, and it produced
a favourable outcome, it is my view that that in itself is not proof of
the proposition.

Whilst one favourable experiment cannot proove the proposition correct,
just one valid experiment can prove the proposition to be not generally
true. No doubt the reason for the focus on proving experiments invalid.

If you give some thought to what you could use Zs for, then every valid
experiment that is designed around that application must produce a
favourable outcome if Zs is as proposed. If they don't, then the value
assumed for Zs must be wrong.

I posted a simple test earlier that in my experience does not support the
proposition that typical ham HF transmitters have Zs=50+j0 or close to
it. The test is documented so that individuals can try it and make their
own mind up. Some might get favourable results on limited trials... but
in my view, that is outweighed by unfavourable results from valid
experiments.

Owen

Keith,

Assertions have been made about the Thevenin equivalent source impedance
(Zs) of an RF PA. In the discussions over the years, some people have
imposed some qualifications (eg classes, tuned / untuned etc).

Zs can be measured by a number of methods. It is interesting to note that
in many of the discussions on the 'net on this topic, more focus is given
to dismissing the experiment design for experiments that produce
unfavourable results to some, than questioning the proposition that Zs is
50+j0 or thereabouts.

Whilst Walt has documented a quite rigourous experiment, and it produced
a favourable outcome, it is my view that that in itself is not proof of
the proposition.

Whilst one favourable experiment cannot proove the proposition correct,
just one valid experiment can prove the proposition to be not generally
true. No doubt the reason for the focus on proving experiments invalid.

If you give some thought to what you could use Zs for, then every valid
experiment that is designed around that application must produce a
favourable outcome if Zs is as proposed. If they don't, then the value
assumed for Zs must be wrong.

I posted a simple test earlier that in my experience does not support the
proposition that typical ham HF transmitters have Zs=50+j0 or close to
it. The test is documented so that individuals can try it and make their
own mind up. Some might get favourable results on limited trials... but
in my view, that is outweighed by unfavourable results from valid
experiments.

Owen

Owen, I have reviewed your simple test using an ATU to obtain various
load impedances, but I don't see any data showing the results of any
tests you may have made using this procedure. I'm assuming it's the
same procedure I used in measuring the data I presented in Chapter 19
of Reflections 2, in which I varied the load impedance by switching
between two different, but closely related values of load resistance.

Unless we're discussing RF power amps using solid-state components, I
don't understand why anyone would expect the source impedance to be 50
+ j0 ohms unless the source was delivering all its available power
into a 50 + j0 load.

I've made an addition to Chapter 19 as it appears in Reflections 2.
That addition now appears in the new edition, Reflections 3. In that
addition I report the procedure and results of measuring the output
impedance of a Kenwood TS-830S terminated in a complex load of 17.98 +
j8.77 ohms. I described fourteen steps in the procedure that resulted
in the measured output impedance of the Kenwood to be 18 - j8 ohms,
which is sufficiently close to the conjugate of the load to be a
practical conjugate match between the source and load impedances.

Why then do you discount the data from my measurements as not proof
that the 18 - j8 ohms of source impedance is valid?

I'm going to try to insert a copy of the 14 steps of the procedure.
However, as I have tried this type of insertion previously and failed,
it also may fail here. If it fails I invite you to go to my web page
at www.w2du.com and click on the line "Preview Chapters from
Reflections 3" and then click on Chapter 19A, then scroll down to Sec
19A.5 Additional Experimental Data. There you will see the detailed
description of the entire procedure. I hope this will help in
understanding my posistion concerning the measurement of the source
impedance at the output of the tank circuit of an RF power amplifier.

Sec 19.14 Additional Experimental Data

The source resistance data reported in Secs 19.8 and 19.9 were
obtained using the load variation method with resistive loads. Note
that of the six measurements of output source resistance reported in
Table 19.1, the average value of the resistance is 50.3 ohms obtained
with the reference load resistance of 51.2 ohms, exhibiting an error
of only 1.8 percent. However, various critics assert that proof of a
conjugate match between the source and load requires the load to
contain reactance. Accordingly, the experimental data reported below
were obtained using both the load variation method and an indirect
method for determining the source impedance of the RF power amplifier,
with a resistive load to obtain a reference source resistance and a
complex load to determine the complex source impedance that is then
proven to be the conjugate of the complex load.
We’ll now examine the experimental data that resulted from
measurements performed subsequent to those reported in Secs 19.8 and
19.9, new data that provides additional evidence that a conjugate
match exists at the output terminals of an RF power amplifier when all
of its available power is delivered into its load, however complex the
load impedance. According to the definition of the conjugate match as
explained in Sec 19.1, Axioms 1 and 2, if this condition prevails
there is a conjugate match. In addition, the data presented below also
provides further evidence that the output source resistance of the RF
amplifier is non-dissipative. The following steps describe the
experimental procedure I employed and the results obtained:

1. Using a Kenwood TS-830S transceiver as the RF source, the tuning
and loading of the pi-network are adjusted to deliver all the
available power into a 50 + j0-ohm load with the grid drive adjusted
to deliver the maximum of 100 watts at 4 MHz, thus establishing the
area of the RF power window at the input of the pi-network, resistance
RLP at the plate, and the slope of the load line. The output source
resistance of the amplifier in this condition will later be shown to
be 50 ohms. In this condition the DC plate voltage is 800 v and plate
current is 260 ma. DC input power is therefore 800 v ï‚´ 0.26 a = 208 w.
Readings on the Bird 43 wattmeter indicate 100 watts forward and zero
watts reflected. (100 watts is the maximum RF output power available
at this drive level.) From here on the grid drive is left undisturbed,
and the pi-network controls are left undisturbed until Step 10.

2. The amplifier is now powered down and the load resistance RL is
measured across the input terminals of the resonant pi-network tank
circuit (from plate to ground) with an HP-4815 Vector Impedance Meter.
The resistance is found to be approximately 1400 ohms. Because the
amplifier was adjusted to deliver the maximum available power of 100
watts prior to the resistance measurement, the averaged resistance RLP
looking into the plate (upstream from the network terminals) is also
approximately 1400 ohms. Accordingly, a non-reactive 1400-ohm resistor
is now connected across the input terminals of the pi-network tank
circuit and source resistance ROS is measured looking rearward into
the output terminals of the network. Resistance ROS was found to be 50
ohms.

3. Three 50-ohm dummy loads (a 1500w Bird and two Heathkit Cantennas)
are now connected in parallel to provide a purely resistive load of
16.67 ohms, and used to terminate a coax of 13.5° length at 4 MHz.

4. The impedance ZIN appearing at the input of the 13.5° length of
coax at 4 MHz terminated by the 16.67-ohm resistor of Step 3 is
measured with the Vector Impedance Meter, and found to be 20 ohms at �
+26°. Converting from polar to rectangular notation, ZIN = 17.98 +
j8.77 ohms. (ZIN = ZLOAD from the earlier paragraphs.) This impedance
is used in Steps 5 and 6 to provide the alternate load impedance in
the load-variation method for determining the complex output impedance
of the amplifier, and for proving that the conjugate match exists.

5. With respect to 50 ohms, ZIN from Step 4 yields a 2.88:1 mismatch
and a voltage reflection coefficient rho = 0.484. Therefore, power
reflection coefficient rho^2 = 0.235, transmission coefficient (1 –
rho^2) = 0.766, and forward power increase factor 1/(1 – rho^2) =
1/0.766 = 1.306.

6. Leaving pi-network and drive level adjustments undisturbed, the 50-
ohm load is now replaced with the coax terminated with the 16.67-ohm
load from Step 4, thus changing the load impedance from 50 + j0 ohms
to 17.98 + j8.77 ohms, the input impedance ZIN of the coax.

7. Due to the 2.88:1 mismatch at the load, neglecting network losses
and the small change in plate current resulting from the mismatch,
approximately the same mismatch appears between RLP and ZL at the
input of the pi-network. Consequently, the change in load impedance
changed the network input resistance RL from 1400 ohms to complex ZL =
800 – j1000 ohms, measured with the Vector Impedance Meter using the
method described in Step 2. To verify the impedance measurement of ZL
the phase delay of the network was measured using an HP-8405 Vector
Voltmeter and found to be 127°. Using this value of phase delay the
input impedance ZL was calculated using two different methods; one
yielding 792 – j1003 ohms, the other yielding 794.6 – j961.3 ohms,
thus verifying the accuracy of the measurement. However, although grid
voltage EC, grid drive EG, are left unchanged, resistance RLP of
approximately 1400 ohms at the plate has changed somewhat due to the
small changes in plate voltage and plate current due to the change in
the load, leaving a mismatch between RLP and ZL at the input of the pi-
network. As stated above, this value of ZL yields the substantially
the same mismatch to plate resistance RLP as that between the output
impedance of the pi-network and the 17.98 + j8.77-ohm load, i.e.,
2.88:1. This mismatch at the network input results in less power
delivered into the network, and thus to the load, a decrease in the
area of the RF window at the network input, and a change in the slope
of the loadline. (It must be remembered that the input and output
mismatches contribute only to mismatch loss, which does not result in
power delivered and then lost somewhere in dissipation. As we will see
in Step 8, the mismatch at the input of the pi-network results only in
a reduced delivery of source power proportional to the degree of
mismatch.)

8. Readings on a Bird 43 power meter now indicate 95w forward and 20w
reflected, meaning only 75 watts are now delivered by the source and
absorbed in the mismatched load. The 20w reflected power remains in
the coax, and adds to the 75 watts delivered by the source to
establish the total forward power of 95w.

9. We now compare the measured power delivered with the calculated
power, using the power transmission coefficient, 1 – rho^2. The
calculated power delivered is: 100w x (1 – rho^2) = 76.6w, compared to
the 75w indicated by the Bird wattmeter. However, because the new
load impedance is less than the original 50 ohms, and also reactive,
the amplifier is now overloaded and the pi-network is detuned from
resonance. Consequently, the plate current has increased from 260 to
290 ma, plate voltage has dropped to 760 v, and DC input power has
increased from 208 w to 220.4 w.

10. With the 17.98 + j8.77-ohm load still connected, the pi-network
loading and tuning are now re-adjusted to again deliver all available
power with drive level setting still left undisturbed. The
readjustment of the plate tuning capacitor has increased the
capacitive reactance in the pi-network by –8.77 ohms, canceling the
+8.77 ohms of inductive reactance in the load, returning the system to
resonance. The readjustment of the loading control capacitor has
decreased the output capacitive reactance, thus reducing the output
resistance from 50 to 17.98 ohms. Thus the network readjustments have
decreased the output impedance from 50 + j0 to 17.98 – j 8.77 ohms,
the conjugate of the load impedance, 17.98 + j8.77 ohms. The
readjustments have also returned the network input impedance ZL to
1400 + j0 ohms (again equal to RLP), have returned the original area
of the RF window at the network input, and have returned the slope of
the loadline to its original value. For verification of the 1400-ohm
network input resistance after the readjustment, ZL was again measured
using the method described in Step 2, and found it to have returned to
1400 + j0 ohms.

11. Bird 43 power meter readings following the readjustment procedure
now indicate 130w forward and 29.5w reflected, indicating 100.5w
delivered to the mismatched load.

12. For comparison, the calculated power values a Forward power =
100 x 1.306 = 130.6w, reflected power = 30.6w, and delivered power =
130.6w – 30.6w = 100w showing substantial agreement with the measured
values. (1.306 is the forward power increase factor determined in Step
5.) Plate current has returned to its original value, 260 ma, and
likewise, plate voltage has also returned to the original value, 800
v. Consequently, the DC input power has also returned to its original
value, 208 w.

13. It is thus evident that the amplifier has returned to delivering
the original power, 100 watts into the previously mismatched complex-
impedance load, now conjugately matched, the same as when it was
delivering 100 watts into the 50-ohm non-reactive load. But the
reflected power, 30.6 watts, remains in the coax, adding to the 100
watts delivered by the amplifier to establish the 130.6 watts of
forward power, proving that it does not enter the amplifier to
dissipate and heat the network or the tube.

It must be kept in mind that impedance ZIN appearing at the input
of the 13° line connecting the 16.7-ohm termination to the output of
the amplifier is the result of reflected waves of both voltage and
current, and thus reflected power is returning to the input of the
line, and becomes incident on the output of the amplifier.
The significance of these measurement data is that for the
amplifier to deliver all of its available power (100w) into the
mismatched load impedance ZIN = 17.98 + j8.77 ohms, the readjustment
of the tuning and loading of the pi-network simply changed the output
impedance of the network from 50 + j0 ohms to 17.98 – j8.77 ohms, the
conjugate of the load impedance, thus matching the output impedance of
the network to the input impedance of the coax. Consequently, there is
a conjugate match between the output of the transceiver and its
complex load. QED. The readjustments of the pi-network simply changed
its impedance transformation ratio from 50:1400 to (17.98 – j8.77):
1400, returning the input resistance RL of the pi-network to 1400
ohms, the value of RLP. Thus the plates of the amplifier tubes are
unaware of the change in external load impedance.

14. We’ll now make an additional indirect measurement of ROS that
proves the conjugate match statement above is true. Leaving the pi-
network adjustments undisturbed from the conditions in Step 10, with
the amplifier powered down we again connect a 1400-ohm non-reactive
resistor across the input terminals of the pi-network tank circuit and
measure impedance ZOS looking rearward into the output terminals of
the network. The impedance was found to be ZOS = 18 – j8 ohms.

From a practical viewpoint, measured impedance ZOS = 18 – j8 ohms
is the conjugate of load impedance ZLOAD = 17.98 + j8.77, proving that
the amplifier is conjugately matched to the load, and also proving the
validity of the indirect method in determining that the source
impedance of the amplifier is the conjugate of the load impedance when
all available power is being delivered to the load.
Thus the data obtained in performing Steps 1 through 14 above
proves the following four conditions to be true:


No reflected power incident on the output of the amplifier is
absorbed or dissipated in the amplifier, because:

1. The total DC input power is the same whether the amplifier is
loaded to match the resistive Z0 load of 50 + j0 ohms, with no
reflected power, or to match the complex load of 17.98 – j8.77 ohms
with 30.6 watts of reflected power, while 100 w is delivered to either
the Z0 load or the re-matched complex load.

2. All the 100 watts of power delivered by the transmitter is absorbed
in both the Z0 load and the re-matched complex load cases, with the
same DC input power in both cases.

3. All the 30 watts of reflected power has been shown to add to the
source power, establishing the total 130 watts of forward power in the
case involving the re-matched complex load.

4. All the reflected power is added to the source power by re-
reflection from the non-dissipative output source resistance ROS of
the amplifier. Had the output source resistance of the amplifier been
dissipative the reflected power would have been dissipated there into
heat, instead of being re-reflected back into the line and adding to
the source power. In addition, the Bird 43 power meter would have
indicated 75 watts of forward power, not 95. This proves that
reflected power incident on the output of the amplifier does not cause
heating of the tube.

It should also be noted, an accepted alternative to the load-
variation method for measuring the output impedance of a source of RF
power is the indirect method demonstrated above. As performed during
the measurements described above, the procedure for this method is to
first make the necessary loading adjustments of the output network to
ensure that all of the available power is being delivered to the load.
Next, the input impedance of the load is measured. It then follows
that, as proven above, the source impedance is the conjugate of the
input impedance measured at the input of the load, because when all
available power is being delivered to the load, this condition
conforms to the Conjugate Matching and the Maximum Power-transfer
Theorems17.
Additionally, I previously performed this same measurement
procedure using a HeathKit HW-100 transceiver, using several different
lengths of coax between the 16.7-ohm load and the output of the
transceiver in each of several measurements. The different lengths of
coax provided different complex load impedances for the transceiver
during each measurement. The same performance as described above
resulted with each different load impedance, providing further
evidence that a conjugate match exists when the amplifier is
delivering all of its available power into its load. These results
also prove that the single test with the Kenwood transceiver is not
simply a coincidence.

Walt, W2DU

On Fri, 28 May 2010 00:08:10 GMT, Owen Duffy wrote:

Zs can be measured by a number of methods. It is interesting to note that
in many of the discussions on the 'net on this topic, more focus is given
to dismissing the experiment design for experiments that produce
unfavourable results to some, than questioning the proposition that Zs is
50+j0 or thereabouts.

Hi Owen,

Even this Zs = 50+j0 or thereabouts is a distraction. Quite simply,
being able to reject a single value is an evasion of facing the
evidence of source resistance.

What is more comic is both sides couldn't agree more! Truly Kabuki.

Whilst Walt has documented a quite rigourous experiment, and it produced
a favourable outcome, it is my view that that in itself is not proof of
the proposition.

Propositions seem to abound as n+1 the number of participants. I dare
say no two participants can agree what any single proposition is
without adorning further distractions to it like bulbs on a Christmas
tree.

Whilst one favourable experiment cannot proove the proposition correct,
just one valid experiment can prove the proposition to be not generally
true. No doubt the reason for the focus on proving experiments invalid.

Proving a straw man invalid is simple. Proving a murky proposition
invalid is simple too. Unfortunately, the occurrences of actually
stepping up to the bench and showing results other and conclusively
different from those offered is a void in the discussion.

It would seem the qualitative counter-proof comes cheap and that
submitted quantifiables are unchallenged. Quite a paradox.

If you give some thought to what you could use Zs for, then every valid
experiment that is designed around that application must produce a
favourable outcome if Zs is as proposed. If they don't, then the value
assumed for Zs must be wrong.

I posted a simple test earlier that in my experience does not support the
proposition that typical ham HF transmitters have Zs=50+j0 or close to
it. The test is documented so that individuals can try it and make their
own mind up. Some might get favourable results on limited trials... but
in my view, that is outweighed by unfavourable results from valid
experiments.

For years I have read that Zs is not ____. Just as quantifiables are
brushed off the table of discussion, I have yet to see measure of what
the objectors' Zs IS instead under any circumstance that they can
conveniently arrange with their own tools and source.

It is a tautology that if it is not X, it must be Y, or Z, or.... None
seem to know an explicit answer under any circumstance or
configuration of their own gear. Without some value such as 10 Ohms,
50 Ohms, 10,000 Ohms, it leaves a most curious happenstance that any
garden variety ham transmitter exhibits either 0 or infinite source
resistance - but I dare say no one is going to step forward to accept
these boundary limits either!

No counter-proclaimants of ANY value between and including 0 to
infinity. It would be a commitment anyone could validate or refute on
the basis of science at the bench - and what would follow from that
examination? I would find such discussion refreshing in comparison.

What a happy state of ignorance this topic draws out of the wallpaper.

73's
Richard Clark, KB7QHC

On May 28, 12:21*am, Richard Clark wrote:
On Fri, 28 May 2010 00:08:10 GMT, Owen Duffy wrote:
Zs can be measured by a number of methods. It is interesting to note that
in many of the discussions on the 'net on this topic, more focus is given
to dismissing the experiment design for experiments that produce
unfavourable results to some, than questioning the proposition that Zs is
50+j0 or thereabouts.

Hi Owen,

Even this Zs = 50+j0 or thereabouts is a distraction. *Quite simply,
being able to reject a single value is an evasion of facing the
evidence of source resistance.

What is more comic is both sides couldn't agree more! *Truly Kabuki.

Whilst Walt has documented a quite rigourous experiment, and it produced
a favourable outcome, it is my view that that in itself is not proof of
the proposition.

Propositions seem to abound as n+1 the number of participants. *I dare
say no two participants can agree what any single proposition is
without adorning further distractions to it like bulbs on a Christmas
tree.

Whilst one favourable experiment cannot proove the proposition correct,
just one valid experiment can prove the proposition to be not generally
true. No doubt the reason for the focus on proving experiments invalid.

Proving a straw man invalid is simple. *Proving a murky proposition
invalid is simple too. *Unfortunately, the occurrences of actually
stepping up to the bench and showing results other and conclusively
different from those offered is a void in the discussion. *

It would seem the qualitative counter-proof comes cheap and that
submitted quantifiables are unchallenged. *Quite a paradox.

If you give some thought to what you could use Zs for, then every valid
experiment that is designed around that application must produce a
favourable outcome if Zs is as proposed. If they don't, then the value
assumed for Zs must be wrong.

I posted a simple test earlier that in my experience does not support the
proposition that typical ham HF transmitters have Zs=50+j0 or close to
it. The test is documented so that individuals can try it and make their
own mind up. Some might get favourable results on limited trials... but
in my view, that is outweighed by unfavourable results from valid
experiments.

For years I have read that Zs is not ____. *Just as quantifiables are
brushed off the table of discussion, I have yet to see measure of what
the objectors' Zs IS instead under any circumstance that they can
conveniently arrange with their own tools and source. *

It is a tautology that if it is not X, it must be Y, or Z, or.... None
seem to know an explicit answer under any circumstance or
configuration of their own gear. *Without some value such as 10 Ohms,
50 Ohms, 10,000 Ohms, it leaves a most curious happenstance that any
garden variety ham transmitter exhibits either 0 or infinite source
resistance - but I dare say no one is going to step forward to accept
these boundary limits either! *

No counter-proclaimants of ANY value between and including 0 to
infinity. *It would be a commitment anyone could validate or refute on
the basis of science at the bench - and what would follow from that
examination? *I would find such discussion refreshing in comparison.

What a happy state of ignorance this topic draws out of the wallpaper.

73's
Richard Clark, KB7QHC

Richard, I'm not sure I understand thrust of your theme correctly. Are
you accepting my measurement data as proof of my position, or are you
including my data as a happy state of ignorance on this topic?

Walt, W2DU

On Fri, 28 May 2010 08:18:44 -0700 (PDT), walt wrote:

Richard, I'm not sure I understand thrust of your theme correctly. Are
you accepting my measurement data as proof of my position, or are you
including my data as a happy state of ignorance on this topic?

Walt, W2DU

Hi Walt,

You understand my "truly kabuki" suitably enough, which means the
others must be lurking in the shadows unable to step up to the bench
of their own demonstrable scientific commitment.

Your numbers show evidence of source resistance. Like any real
resistance, in a complex mix of reactances and phases, all
superposition energies collapse to reveal a net value that is either a
caloric break-even, gain, or loss. This real resistance is the
experience of EVERY correspondent here.

As for your position, your proposal appears to exhibit source
resistance where you deny its reality. This is a longstanding
difference we have had and I presume will never be bridged.

If you had never opened the door to the conjugate match, because what
you argue with your data as support is properly an image-Z match, then
you would be on a firmer foundation, rhetorically.

The Z match more close corresponds to the maximum available power
transfer theorem and models of Thevenin/Norton sources. Neither of
these sources demand a resistor - this was a high school physics
artifact with about as much rigor as Sunday school is to theology.

Terman explicitly offers Thévenin's Theorem on the bottom of page 74
continuing onto page 75. He describes the Z match in the middle of
page 76. Your argument is what Terman calls an "image-impedance
basis." Note the term "basis," it has been my question to you for
years as to what basis you have used. I have never gotten an explicit
response.

In the second paragraph of 3-8 we find Terman discuss the conjugate
basis of matching for maximum available power delivery. I won't
belabor what can be read by the multitudes for themselves.

However, beyond this discussion, Terman offers an APPLICATION where
its topology is entirely congruent with the propositions being bandied
about here. Please turn to pages 262, 263 footnotes to observe plate
resistance and grid-leak resistance being offered - not Zs but Rs.

This last point, yet another distraction, probably brings a collective
sigh of relief as the shadows are emptied with those who throng to
argue the meaning of resistance instead of measuring it at their own
bench.

Truly Kabuki.

73's
Richard Clark, KB7QHC

On May 28, 1:56*pm, Richard Clark wrote:
On Fri, 28 May 2010 08:18:44 -0700 (PDT), walt wrote:
Richard, I'm not sure I understand thrust of your theme correctly. Are
you accepting my measurement data as proof of my position, or are you
including my data as a happy state of ignorance on this topic?

Walt, W2DU

Hi Walt,

You understand my "truly kabuki" suitably enough, which means the
others must be lurking in the shadows unable to step up to the bench
of their own demonstrable scientific commitment.

Your numbers show evidence of source resistance. *Like any real
resistance, in a complex mix of reactances and phases, all
superposition energies collapse to reveal a net value that is either a
caloric break-even, gain, or loss. *This real resistance is the
experience of EVERY correspondent here.

As for your position, your proposal appears to exhibit source
resistance where you deny its reality. *This is a longstanding
difference we have had and I presume will never be bridged.

If you had never opened the door to the conjugate match, because what
you argue with your data as support is properly an image-Z match, then
you would be on a firmer foundation, rhetorically.

The Z match more close corresponds to the maximum available power
transfer theorem and models of Thevenin/Norton sources. *Neither of
these sources demand a resistor - this was a high school physics
artifact with about as much rigor as Sunday school is to theology.

Terman explicitly offers Thévenin's Theorem on the bottom of page 74
continuing onto page 75. *He describes the Z match in the middle of
page 76. *Your argument is what Terman calls an "image-impedance
basis." *Note the term "basis," it has been my question to you for
years as to what basis you have used. *I have never gotten an explicit
response.

In the second paragraph of 3-8 we find Terman discuss the conjugate
basis of matching for maximum available power delivery. *I won't
belabor what can be read by the multitudes for themselves. *

However, beyond this discussion, Terman offers an APPLICATION where
its topology is entirely congruent with the propositions being bandied
about here. *Please turn to pages 262, 263 footnotes to observe plate
resistance and grid-leak resistance being offered - not Zs but Rs. *

This last point, yet another distraction, probably brings a collective
sigh of relief as the shadows are emptied with those who throng to
argue the meaning of resistance instead of measuring it at their own
bench.

Truly Kabuki.

73's
Richard Clark, KB7QHC

Hello Richard,

I must be honest with you, Richard, for over the years I have often
been in a quandary after reading some of your posts--I simply don't
comprehent what you're saying in them. I often have to turn to look at
some one else and ask " wad't he say? wad't he say?" For example, I
don't know what a 'kabuki' is.

You say my numbers show evidence of a source resistance. Then you also
say "This real resistance is the
experience of EVERY correspondent here." On the contrary, my
understanding is that Keith Dysart and Owen Duffy don't agree with
that. Have I misunderstood their posts? Then you say,"What is more
comic is both sides couldn't agree more! Truly Kabuki." Again, what
is 'kabuki'? In other words, to both sides agree or disagree? Which is
it?

In another paragraph you say, "As for your position, your proposal
appears to exhibit source resistance where you deny its reality. This
is a longstanding difference we have had and I presume will never be
bridged." I totally misunderstand that statement, especially a
longstanding difference that I didn't know we had. And although my
measurements of source impedance (or resistance) indicate their
reality, I have never knowingly denied their reality. I can't
understand how you could have reasoned that I denied it.

Now we come to the "basis" for my measurements. You state that my
measurements appear to be on the basis of image impedances. According
to my editions of both Terman and Everitt, 'image' impedances mean
that when the generator is connected to the input terminals of the
network the impedances looking in both directions at the output
terminals of a network are equal. I understand that this can be true
if the impedances are purely resistive, but I can't see how this could
be true when the impedances are complex, having reactive components.
If the impedances in both direction contain equal reactances (not
opposite), then delivery of maximum available power cannot be
delivered. For the maximum power to be delivered the reactances
looking in opposite directions MUST also be OPPOSITE, describing a
conjugate relationship, not an image relationship.

Unfortunately, my editions of Terman must be different from yours,
because I find no mention of plate resistance (Rp) or Rs. Rp is a
factor in determining the value of RL that appears at the input of a
pi-network in an RF power amp, but has no relevancy downstream of the
network input, and certainly has no relevance to the formation of a
conjugate match at the output of the network.

So Richard, let me get this straight--are you agreeing with my
position or disagreeing?

Kabuki?

Walt

On Fri, 28 May 2010 16:43:42 -0700 (PDT), walt wrote:

Hello Richard,

I must be honest with you, Richard, for over the years I have often
been in a quandary after reading some of your posts--I simply don't
comprehent what you're saying in them. I often have to turn to look at
some one else and ask " wad't he say? wad't he say?" For example, I
don't know what a 'kabuki' is.

Hi Walt,

Your confusion is well founded. :-)

Kabuki - Japanese theatre with very elaborate costumes and highly
mannered acting. It is presented in day long plays that many in the
audience feel perfectly at ease with watching, talking to a neighbor,
eating a meal during the performance or taking a break and coming back
to after an hour or so.

You say my numbers show evidence of a source resistance. Then you also
say "This real resistance is the
experience of EVERY correspondent here." On the contrary, my
understanding is that Keith Dysart and Owen Duffy don't agree with
that. Have I misunderstood their posts? Then you say,"What is more
comic is both sides couldn't agree more! Truly Kabuki." Again, what
is 'kabuki'? In other words, to both sides agree or disagree? Which is
it?

Both. However, as to why? They themselves are notably absent from
this discussion. I mark this as a lack of commitment at the bench to
obtain contrary evidence. Perhaps it is casual indifference carefully
woven into passionate and emphatic negations. Such bipolar swings is
what I term as truly Kabuki.

In another paragraph you say, "As for your position, your proposal
appears to exhibit source resistance where you deny its reality. This
is a longstanding difference we have had and I presume will never be
bridged." I totally misunderstand that statement, especially a
longstanding difference that I didn't know we had. And although my
measurements of source impedance (or resistance) indicate their
reality, I have never knowingly denied their reality. I can't
understand how you could have reasoned that I denied it.

On Thu, 27 May 2010 13:15:49 -0700 (PDT), walt wrote:

Rp is NOT the source resistance.

Note your emphasis in the original. It conforms to half the other
writers half the time (who can tell with all their mannered
elaboration?).

If you can allow that Rp is real resistance, all fine and well. If it
takes more than three sentences to state it is not, then that is truly
Kabuki. Three sentences may not completely give you enough freedom of
expression, but if I see a fire hose response - that is just too much
material to justify parsing for a clear answer.

Now we come to the "basis" for my measurements. You state that my
measurements appear to be on the basis of image impedances. According
to my editions of both Terman and Everitt, 'image' impedances mean
that when the generator is connected to the input terminals of the
network the impedances looking in both directions at the output
terminals of a network are equal. I understand that this can be true
if the impedances are purely resistive, but I can't see how this could
be true when the impedances are complex, having reactive components.

Well, you have the material at hand. Terman offers succinct meaning.
A position is usually in one place. That place is as Terman and NBS
writer Stephen Adam (strictly) terms it as "basis." And I asked what
basis you use. Please consult the strict usages of the literal word
basis (and not the informal understanding of "how") to avoid mixing
them. Your pleas are often couched with conjugate basis and you
attempt to prove them with image-Z basis. They should not be
intermingled.

If the impedances in both direction contain equal reactances (not
opposite), then delivery of maximum available power cannot be
delivered. For the maximum power to be delivered the reactances
looking in opposite directions MUST also be OPPOSITE, describing a
conjugate relationship, not an image relationship.

Unfortunately, my editions of Terman must be different from yours,

You do not have "Electronic and Radio Engineering?"

So Richard, let me get this straight--are you agreeing with my
position or disagreeing?

I take no position beyond your data clearly exhibiting the nature of
what Terman describes in pages I have referenced. My professional
experience has been invested with measuring real resistance to NBS
precision and accuracy - this includes plate and collector resistances
(albeit at vastly less resolution than standard resistors and such).

Energy creates heat in real resistors. The combination of phases and
energies in a resistance still gives rise to heat, if by different
degrees that follow phase relationships of all perceived sources. Heat
can increase through soaking (a steady elevated current) or through
breakdown (the quick flash of an intense voltage arc). These two are
very common (even if only on rare occasions) experiences of EVERY
correspodent with their own equipment. It is exceptional to deny
this. We have exceptional threads.

Your data does not contradict any of my points - the question is: does
your position contradict Terman's discussion and my experience? I
have trouble with your mixed basis discussion that clouds my ability
to resolve where you stand. Other writers seem to go both ways
without any data of their own measurements to inform me about their
judgment having authority. Yours is the only data (aside from my own
offered earlier in separate discussion) on the table - and it suits me
fine.

73's
Richard Clark, KB7QHC

On May 28, 9:05*pm, Richard Clark wrote:
On Fri, 28 May 2010 16:43:42 -0700 (PDT), walt wrote:
Hello Richard,

I must be honest with you, Richard, for over the years I have often
been in a quandary after reading some of your posts--I simply don't
comprehent what you're saying in them. I often have to turn to look at
some one else and ask *" wad't he say? wad't he say?" For example, I
don't know what a 'kabuki' is.

Hi Walt,

Your confusion is well founded. *:-)

Kabuki - Japanese theatre with very elaborate costumes and highly
mannered acting. *It is presented in day long plays that many in the
audience feel perfectly at ease with watching, talking to a neighbor,
eating a meal during the performance or taking a break and coming back
to after an hour or so.

You say my numbers show evidence of a source resistance. Then you also
say "This real resistance is the
experience of EVERY correspondent here." *On the contrary, my
understanding is that Keith Dysart and Owen Duffy don't agree with
that. Have I misunderstood their posts? Then you say,"What is more
comic is both sides couldn't agree more! *Truly Kabuki." Again, what
is 'kabuki'? In other words, to both sides agree or disagree? Which is
it?

Both. *However, as to why? *They themselves are notably absent from
this discussion. *I mark this as a lack of commitment at the bench to
obtain contrary evidence. *Perhaps it is casual indifference carefully
woven into passionate and emphatic negations. *Such bipolar swings is
what I term as truly Kabuki.

In another paragraph you say, *"As for your position, your proposal
appears to exhibit source resistance where you deny its reality. *This
is a longstanding difference we have had and I presume will never be
bridged." I totally misunderstand that statement, especially a
longstanding difference that I didn't know we had. And although my
measurements of source impedance (or resistance) indicate their
reality, I have never knowingly denied their reality. I can't
understand how you could have reasoned that I denied it.
On Thu, 27 May 2010 13:15:49 -0700 (PDT), walt wrote:

Rp is NOT the source resistance.

Note your emphasis in the original. *It conforms to half the other
writers half the time (who can tell with all their mannered
elaboration?).

If you can allow that Rp is real resistance, all fine and well. *If it
takes more than three sentences to state it is not, then that is truly
Kabuki. *Three sentences may not completely give you enough freedom of
expression, but if I see a fire hose response - that is just too much
material to justify parsing for a clear answer.

Now we come to the "basis" for my measurements. You state that my
measurements appear to be on the basis of image impedances. According
to my editions of both Terman and Everitt, 'image' impedances mean
that when the generator is connected to the input terminals of the
network the impedances looking in both directions at the output
terminals of a network are equal. I understand that this can be true
if the impedances are purely resistive, but I can't see how this could
be true when the impedances are complex, having reactive components.

Well, you have the material at hand. *Terman offers succinct meaning.
A position is usually in one place. *That place is as Terman and NBS
writer Stephen Adam (strictly) terms it as "basis." *And I asked what
basis you use. *Please consult the strict usages of the literal word
basis (and not the informal understanding of "how") to avoid mixing
them. *Your pleas are often couched with conjugate basis and you
attempt to prove them with image-Z basis. *They should not be
intermingled.

If the impedances in both direction contain equal reactances (not
opposite), then delivery of maximum available power cannot be
delivered. For the maximum power to be delivered the reactances
looking in opposite directions MUST also be OPPOSITE, describing a
conjugate relationship, not an image relationship.

Unfortunately, my editions of Terman must be different from yours,

You do not have "Electronic and Radio Engineering?"

So Richard, let me get this straight--are you agreeing with my
position or disagreeing?

I take no position beyond your data clearly exhibiting the nature of
what Terman describes in pages I have referenced. *My professional
experience has been invested with measuring real resistance to NBS
precision and accuracy - this includes plate and collector resistances
(albeit at vastly less resolution than standard resistors and such). *

Energy creates heat in real resistors. *The combination of phases and
energies in a resistance still gives rise to heat, if by different
degrees that follow phase relationships of all perceived sources. Heat
can increase through soaking (a steady elevated current) or through
breakdown (the quick flash of an intense voltage arc). *These two are
very common (even if only on rare occasions) experiences of EVERY
correspodent with their own equipment. *It is exceptional to deny
this. *We have exceptional threads.

Your data does not contradict any of my points - the question is: does
your position contradict Terman's discussion and my experience? *I
have trouble with your mixed basis discussion that clouds my ability
to resolve where you stand. *Other writers seem to go both ways
without any data of their own measurements to inform me about their
judgment having authority. *Yours is the only data (aside from my own
offered earlier in separate discussion) on the table - and it suits me
fine.

73's
Richard Clark, KB7QHC

Richard, I'm still trying to assimilate all the info you presented in
you post above. So please allow me to skate around a bit.

First, concerning plate resistance, Rp. This may be where we don't
understand each other. My position on Rp is that it is a non-
dissipative resistance, and can be measured by noting the change in Ip
with a change in ep with grid voltage held constant. The result of the
effect of Rp is thus one of inverse feedback when the Ip is varying
with respect to a change in grid voltage that causes a change in Ip
that is inversely related to the change in ep appearing across the
plate load resistance with the plate source voltage held constant. Rp
thus is not relevant to the source resistance of an RF power amplifier
other than its effect on RL looking upstream of the input to the pi-
network. When I speak of the source resistance (or impedance) of the
RF power amp I'm referring to the resistance (or impedance) appearing
at the output terminals of the network, which has nothing to do with
Rp. If you're considering Rp as the source resistance that's probably
the reason for our disagreement, and if you do consider Rp as the
source resistance I believe you're wrong.

And concerning the basis for the impedance matching, I don't consider
that I'm comingling image impedance with conjugate impedance. I simply
can't construe Terman's definition of 'image' impedance as relating to
the procedure I used in measuring the source impedance appearing at
the output of the network. This is because Terman says the image
impedance at the output terminals of the network is the same looking
in both directions. This condition cannot occur when the reactance
component in the load is the opposite to that looking rearward into
the network, a condition required to satisfy the Maximum Power
Transfer Theorem with respect to delivering all the available power.

However, I will say this, I appreciate your statement that my data
suits you fine.

Walt

On Fri, 28 May 2010 19:09:04 -0700 (PDT), walt wrote:

Richard, I'm still trying to assimilate all the info you presented in
you post above. So please allow me to skate around a bit.

First, concerning plate resistance, Rp. This may be where we don't
understand each other. My position on Rp is that it is a non-
dissipative resistance, and can be measured by noting the change in Ip
with a change in ep with grid voltage held constant.

Hi Walt,

Thank you for the restrained answer. Yes, we do not agree here.

To the matter of the conjugate basis. Terman quite distinctly gives
us a real R that remains after the cancellation of reactances. As a
hallmark of first principles, it is very clear and concise. The
source R must match the load R for the source to deliver the maximum
available power. By the same hallmark, this too is very explicit.
Terman calls this R (the remnant of conjugation) in the source: "the
resistance component of the generator impedance."

For you and others to say what the source is "not," that is not a
solution for what the source "is." This is what I speak of when you
ask if your critics agree or disagree. You stand with your critics
against the testimony of your data that stands with Terman.

The plate resistance can be described physically to suit any objection
that I have so far heard from the community. It suits very few who
embrace thought experiments that have never warmed a bench nor
flickered a measurement instrument. The collapse of rhetoric has
exposed the vacuum of counter argument.

However, I will say this, I appreciate your statement that my data
suits you fine.

Walt, your methods are first methods. Your care for propriety exceeds
all bold statements that carelessly condemn you. Your achievements
give you the status of not having to endure taunts and endless
bickering. Your steadfast self examination and willingness to sit at
the bench is the rock of faith in what Hams aspire for in engineering.
As for your humanity, I find you a proud father and loving husband. I
think of you in no other terms, even when my prose is dense or obtuse,
and my engineering demands are harsh and pointed.

If my allusions to Kabuki are obscure, it is through my upbringing
living in Japan as a tyke. If I might balance that obscure reference
for one that is more to my tone here, I call you Sensei - a master of
learning and teaching.

73's
Richard Clark, KB7QHC