The Dark Side of the Conjugate Match

Discussion in 'General Technical Questions and Answers' started by KL7AJ, Mar 12, 2010.

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  1. W5DXP

    W5DXP Ham Member QRZ Page

    Now we have gone from - 1. It doesn't happen - to 2. It does happen, but it doesn't matter - to 3. It is a waste of time, a last resort diversionary argument designed to avoid answering the question.

    Incidentally, the load does not "tug" on the source. The load furnishes speed-of-light feedback information to the source through reflected EM energy. The feedback from the load is what causes changes in the source. There is no other speed-of-light phenomena known to physics that could cause changes in the source other than reflected energy feedback.

    The load is obviously communicating with the source using speed-of-light signals. Electrons cannot travel at the speed of light. Only photonic traveling wave/field energy could be accomplishing that communications feat and the only energy that exists are in the forward and reflected waves/fields bouncing between the load and the source causing the transient conditions that you describe in the tank circuit. Thanks for the additional example of forward and reflected EM traveling wave/field energy inside the source. EM energy cannot stand still in an RF circuit. It is either moving forward or moving in the reverse direction.

    Your description of the transient state delay before the source settles down is even more proof that forward and reflected energy is rampant inside the source. What phenomena causes the communications from the load to the source that causes all those "tug on the tank" transient delays? There is none of Einstein's "spooky action at a distance" in your example. All communications between the load and the source is EM forward/reflected fields/waves. That is true when there is any speed-of-light delay present. Point is that there is no other known communications method besides forward and reflected energy that could be at work in an RF circuit.

    Note that I am not proposing any quantitative answers. I am presenting qualitative conceptual answers based on the laws of physics. If the photonic EM energy bouncing around inside a source at speed-of-light delays is not forward and reflected energy, exactly what is it? Please be specific.

    Hint: All of the transient signals moving at the speed-of-light in the circuit that you describe prove the presence of EM waves/fields by proving the presence of photons, i.e. the presence of forward and reflected waves/fields rampant inside the source circuitry. If there were no reflected wave/field energy feedback from the load all the way to the source, the source conditions would never change away from the matched condition.

    So it isn't a waste of time because it proves all EM transient phenomena is caused by forward and reflected field/wave energy inside the source. It disproves the contention that reflected energy stops at the source output connector. There is no impedance discontinuity at the source output connector to cause 100% re-reflection of the reflected waves to occur.
     
    Last edited: Sep 20, 2010
  2. AB0WR

    AB0WR Ham Member QRZ Page

    Cecil,

    " There is no other speed-of-light phenomena known to physics that could cause changes in the source other than reflected energy feedback."

    Once again you are offering up the False Dilemma argumentative fallacy.

    *When* it happens isn't important. You can argue till you are blue in the face but it really doesn't matter.

    If Alpha Centauri goes supernova at this very instant does it matter to us? Answer: NO. We will be affected whenever we are affected.

    If the impedance at the output of the load capacitor changes 6ns, 60ns, or 60 years after you change the load it *still* doesn't matter.

    In fact, as JI points out, because of tank circuit action if you change the load and then change it back within one RF cycle, the tank circuit will keep the tube from even seeing it -- even though there will be a different set of reflected waves on the line for a measurable amount of time.

    Using your posit this couldn't happen. The "reflected wave" would *have* to be seen by the tube. Only if lumped components act differently than transmission lines would the tube not see the change in the load. If a tank circuit didn't work this way then you could never use a Class C amp and get a full RF cycle out of the tank.

    The very fact that you can simulate transmission lines with lumped components without having to have the lumped components separated by the same physical length as the transmission line would lead most people to understand that there is a distinct difference between lumped components and transmission lines.

    tim ab0wr
     
  3. W5DXP

    W5DXP Ham Member QRZ Page

    Tim, I am sorry that you are unwilling or incapable of comprehending the importance of some delay vs the zero delay required by the lumped-circuit model. If you were a physicist, you would understand immediately the importance. Perhaps someone else can explain it better than I. Saying that, "it really doesn't matter", is exactly the same as saying that, "cause and effect doesn't matter".

    Simply put, if a delay exists, the lumped-circuit model is invalid and reflected energy is what causes any change in the load-line of an amplifier. It cannot do that unless it (reflected energy) is incident upon the load line which proves that reflected energy is flowing inside the source. That's what the present argument is all about. The delay indicates when the reflected energy is first incident upon the amp's load-line. If the delay is not zero, i.e. the load-line doesn't change exactly when the load is changed, the lumped-circuit model is invalid for telling us anything about the reflected energy.
     
    Last edited: Sep 20, 2010
  4. W5DXP

    W5DXP Ham Member QRZ Page

    Tim, if you want to prove that to be a true statement, you necessarily must prove that the source can change its load-line at exactly the same time the load impedance is changed as required by the lumped-circuit model. If you cannot do that, wouldn't you agree that it's time to question your position?

    This challenge is not just for Tim. For all of you who believe that the source's load-line can change instantaneously every time the load impedance is changed, please prove it because that is what is required for no reflected energy to be flowing in the source.
     
  5. AB0WR

    AB0WR Ham Member QRZ Page

    Cecil,

    Why did you ignore the fact that if you change a load and change it back within one RF cycle that the tube won't even see the change because of the tank action?

    Where did the reflected wave GO?

    The delay in that case is INFINITE!

    Yet the reflected energy obviously exists on the transmission line for at least some period of time.

    And no one said cause and effect don't matter. That is just one more false dilemma you are offering up. Alpha Centauri going supernova would have one heck of an effect on us -- but it doesn't matter one iota when that effect happens. It will happen when it happens.

    Tell us where that reflected energy goes in the transmitter when it lasts less than an RF cycle, Cecil.

    Don't just ignore the issue. Address it directly.
     
  6. AB0WR

    AB0WR Ham Member QRZ Page

    "Tim, if you want to prove that to be a true statement, you necessarily must prove that the source can change its load-line at exactly the same time the load impedance is changed as required by the lumped-circuit model."

    No, I do NOT need to prove that. No one on this thread has offered such a proposition up.

    This is a STRAWMAN of your own making that you are trying to beat the stuffing out of while claiming it isn't your own strawman.

    Not DU or JI or myself have said this.


    " If you cannot do that, wouldn't you agree that it's time to question your position?"

    No, because this isn't our position -- it's a position YOU made up that you want to attribute to us.

    The fact that I say that it doesn't matter WHEN it happens is the exact opposite of this position. I am saying that the timing is irrelevant -- PERIOD. That doesn't require it to be instantaneous in any way, shape, or form.

    "This challenge is not just for Tim. For all of you who believe that the source's load-line can change instantaneously every time the load impedance is changed, please prove it because that is what is required for no reflected energy to be flowing in the source."

    No one is going to prove this because no one is saying this.

    It is NOT required for no reflected energy to be flowing in the source.

    What happens to the reflected energy that lasts less than one RF cycle when it hits a tank circuit? What happens when it lasts less than 1/2 of an RF cycle?

    That's what *YOU* need to prove to make *your* position tenable that a reflected wave will always flow through the lumped components to the source.
     
  7. W5DXP

    W5DXP Ham Member QRZ Page

    If the timing is irrelevant, as you say, then (logically) it could be zero just as easily as any other value. You above statement (logically) indeed does include zero delay time because you certainly did NOT exclude it. If you would like to exclude zero time from your above statement please feel free to do so but realize that such an exclusion would enhance my distributed-network side of the argument.

    The lumped-circuit model requires zero delay time. If you exclude a zero delay time from your assertions then you are discarding the lumped-circuit model and essentially, by process of elimination, supporting my distributed network side of the argument.

    Of course, any implication that I ever said such a thing is pure BS. I am one of the biggest supporters ever for Walt's conjugate match blocking reflected power from reaching the source. If you can produce the posting where I said "a reflected wave will always flow through the lumped components to the source, even in a Z0-matched system", I will send you a check for $1000. Of course, if you cannot find such an assertion, you have to send me a check for $1000 or at least admit that your ethics leave something to be desired.
     
    Last edited: Sep 20, 2010
  8. W5DXP

    W5DXP Ham Member QRZ Page

    Dang Walt, I think you are confusing Tom's position with mine. That's exactly what I have been saying throughout this thread that you and others seem to have been disagreeing with. Do you realize the implications of such a statement? Hint: Reflections are not allowed in the lumped-circuit model! Exactly what prohibits the mismatched reflections from flowing straight through the source output connector and becoming incident upon the source's load-line? IMO, nothing prohibits that from happening.

    What I have been saying is: There is no section of the system, including the source's load-line, that is free of reflected energy when the source is mismatched.

    Sorry, but it seems to me that this posting of yours has reversed your previous position which blows my mind.
     
    Last edited: Sep 20, 2010
  9. WA9CWX

    WA9CWX Ham Member QRZ Page

    This whole issue may make me give up using coax forever.
     
  10. AB0WR

    AB0WR Ham Member QRZ Page

    Folks, don't let Cecil confuse the issue here.

    Unless he can tell us what happens to a reflected wave that is less than an RF cycle long when it hits a lumped circuit tank then he is the one with a time/magic issue here.

    If a lumped circuit tank can *always* be treated as a transmission line then that reflected wave should *always* be transmitted to the source, no matter how long it actually lasts.

    If that reflected wave that is less than a cycle long is NOT transmitted to the source then something else has to have happened to it for it certainly appears on the transmission line connected to the tank circuit.

    If that reflected wave that is less than an RF cycle *is* transmitted to the source then Cecil also needs to explain how a Class C amp transmitting an RF pulse less than a cycle long can use a tank circuit to generate a full cycle of RF. For if the lumped circuit tank can transmit a reflected wave less than an RF cycle long to the source then it should also be able to transmit an RF pulse less than a cycle long from the source to the transmission line.

    The fact that we know the tank circuit doesn't transmit a partial pulse of RF to the transmission line but, instead, transmits a full cycle of RF can only lead to the conclusion that the lumped tank circuit is NOT acting purely as a transmission line.

    So, Cecil, are you claiming magic is at work here? That a tank circuit can transmit a reflected wave less than a cycle long from the transmission line to the source but can't transmit a forward wave less than a cycle long from the source to the transmission line?

    Or is something magic happening to that less than a cycle long reflected wave at the tank circuit that keeps it from being transmitted to the source while a reflected wave longer than a cycle *does* get transmitted?

    Don't keep running away Cecil.

    Tell us what happens in a lumped circuit tank circuit when a less-than-a-cycle reflected wave is seen on the transmission line.

    tim ab0wr
     
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