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

On May 29, 12:26*am, Richard Clark wrote:
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

Hi Richard,

I sincerely appreciate your kind words concerning my humanity, and I'm
proud to have you call me Sensei. I have always somehow doubted your
feelings for me as a person, but your words above have relieved that
feeling, Thank you.

As for our disagreement on image matching, I remember reading many
years ago in books concerning networks involving telephone circuits
that dealt only with resistive terminations. Those readings did
specify that with image resistances the resistances were the same in
both directions. Nothing was said in those books concerning reactance
in the circuitry. Apparently we have different editions of Terman.
Mine doesn't discuss R as the remnant of conjugation, so if only R is
considered in the image impedance I can concur with you on this issue.

I also want to be clear on my position concerning plate resistance Rp
as the source resistance of the RF power amplifier. My position is
that it is not. I do understand that Rp is a factor in determining the
value of RL that appears at the input of the tank circuit, but not the
source of power delivered at the output of the tank circuit. Rp is a
non-dissipative resistance, not a resisTOR with physical
characteristics. I consider the voltage-current ratio R appearing at
the output of the tank circuit to be the source resistance of the RF
power amplifier. If you do not agree with this position then I guess
we'll just have to agree to disagree, unless you can find some way to
change my mind.

I thank you again, Richard, for your kind words.

Walt

On Sat, 29 May 2010 09:43:21 -0700 (PDT), walt wrote:

Apparently we have different editions of Terman.
Mine doesn't discuss R as the remnant of conjugation, so if only R is
considered in the image impedance I can concur with you on this issue.

Hi Walt,

Go to the index and look up Thévenin. The material should be found in
two areas:
1. Circuits with Lumped Constants - Thévenin's Theorem - Impedance
Matching
2. Audio Voltage Amplifiers - Resistance-coupled Amplifiers

Rp is a
non-dissipative resistance, not a resisTOR with physical
characteristics. I consider the voltage-current ratio R appearing at
the output of the tank circuit to be the source resistance of the RF
power amplifier. If you do not agree with this position then I guess
we'll just have to agree to disagree, unless you can find some way to
change my mind.

I will use your own data.

On Thu, 27 May 2010 19:32:40 -0700 (PDT), walt wrote:

In this condition the DC plate voltage is 800 v and plate
current is 260 ma. DC input power is therefore 800 v ? 0.26 a = 208 w.

I will be concerned with nothing else outside of this specification as
this is a discussion of the "real" Tube, and a power supply which will
be considered as loss-less.

First. There is one current loop throughout the entire system.

Second. Unique to a tube path within that current loop, there are two
characteristic current types. These are the convection current WITHIN
the cathode-plate interval, and the induction current that completes
the loop from plate to cathode through conventional power supply
wiring.

Third. The induction current's mobile electrons move at a rate of
meters per minute; whereas the charge mobility is near light speed.

Fourth. The convection current's mobile electrons (a literal particle
stream in a vacuum) move at a rate of near light speed. The term
"near light speed," in this case, is limited by the plate potential of
800V and can be computed; whereas the charge mobility is near light
speed, but generally higher (and specifically higher for 800V) than
the electron speed.

Fifth. It takes work to move an electron initially at rest to near
light speed over the interval between the cathode and the plate with
nanoseconds transit times.

Sixth. The electron gains kinetic energy from the field between the
plate and cathode.

Seventh. The kinetic energy of the electron is converted into heat
upon striking the plate, the heat energy being equal to the power
supply energy expended in accelerating the electron.

I will forgo the math of how considerable the resistance, power, and
heat is. All can be found from the data quoted above. Clearly, the
plate resistance is real in every sense of the word. It is the
limiting factor of the current path hence it is the source resistance
in every sense of the word.

The seven points I enumerate are from material drawn from a single
source. I am sending you the full chapter treatment that speaks to
this topic alone from:
"Physical Electronics," Curtis L. Hemenway, Richard W. Henry, Martin
Caulton; John Wiley and Sons, 1962.

Others may ask for copies of this reference. Others may ask where the
heat comes from, a topic I would enjoy elaborating upon. It is a very
simple explanation that by using Walt's data above, can be rendered
into Watts/Temperature with only the difficulty of pressing calculator
keys. These values than can weighed against real and tested
observation at the bench of the same tube in operation.

I cannot imagine anything else meriting discussion.

73's
Richard Clark, KB7QHC

Walt, W2DU wrote:
"Rp is a non-dissipative resistance, not a tesisTOR with physical
characteristics."

To nit pick a little, I think some dissipative resistance is found in
the output impedance of a Class C amplifier when you average over an RF
cycle.

Although rp (dynamic plate resistance) is defined as the change in plate
voltage divided by the change in plate current when an increment of
plate voltage produces an incremantal change in plate current, plate
resistance goes down as plate current goes up.

Rp can be very low but not zero when a tube biased beyond its cut-off is
pulsed on heavily duting the RF cycle. In saturated conduction the
voltage drop actoss the tube can be very low and any change in plate
voltage would result in insignificant change in plate current.

When a Class C amplifier is switched into heavy conduction by its grid,
its DC resistance is low and its power suppy may be low in resistance
too. During the conduction part of the RF cycle, the impedance looking
back into the amplifier`s putput is low also. During the switched-off
part of the amplifier`s cycle, the impedance looks like an open circuit.
Over an entire cycle, the tube`s output impedance has an average value.

A pi-network is an impedance transformation device which does not
completely isolate its input from its output, so a tube on its input has
its shunt impedance transformed to some value across its output. Its
resonance can linearize the signal.

Best regards, Richard Harrison, KB6WZI