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On Tue, 14 Jun 2011 12:25:33 -0700 (PDT), walt wrote:
Thank you for your insightful response, Richard. However, I must plod on, and introduce the results of my own measurements, the data of which appear in Chapter 19, Sec 19.14 of Reflections 3. Using a Kenwood TS-830S I measured the parameters required to prove the output source resistance of the tank circuit of its RF power amp is non- dissipative. The measurements also prove that the reflected power incident on its output is totally re-reflected. From reading an earlier post of yours, Richard, I know you have read this portion of Chapter 19, and you agreed with it. My measured data conflicts with Best's Eq 8, so there's got to be a valid answer to this dilemma, but where? Walt Hi Walt, Yes, I am very familiar with your bench work. I am very annoyed by those who trivialize it. I am further annoyed by those who patronize you to then shift the parameters to explain something else - completely abandoning you. However, I also acknowledge that I can hurt your feelings about where I stand on these matters. Yes, to a limited degree, I do agree with much of your assessment, but I do not follow it into the arena of where you express it as being "non-dissipative." However, my denying this proposition does NOT mean I dispute your other proposition of complete reflection. This cross connection of several topics is where things get overly complex and gives the entire discussion the appearance of a house of cards. I cannot tell what your agenda is, but the material you quote as source, and for which I have provided links to in this thread - all seem a subtext to non-dissipative sources. Attention directed towards this pursuit of matching points rendered in stubs seems like tea leaf reading to resolve a larger issue. As a student, tech, and engineer employing a LOT of precision waveguide technology, I am quite comfortable with the components and topologies you describe. Arguments for wave interferences being rendered into useful circuit constructs (that is, constructed on the basis of wave interference) has been with us easily since the early 40s. One component, the ATR tube, is one I have handled and replaced to insure the proper operation of RF paths being steered in waveguides. One proviso, however = for any of these "virtualizations" to work, they require a physical (and dissipative) element as the initiator. Waves do not interfere without the presence of a physical element (often some form of detector, or minimally a load). 73's Richard Clark, KB7QHC |
#2
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On Jun 14, 3:53*pm, Richard Clark wrote:
On Tue, 14 Jun 2011 12:25:33 -0700 (PDT), walt wrote: Thank you for your insightful response, Richard. However, I must plod on, and introduce the results of my own measurements, the data of which appear in Chapter 19, Sec 19.14 of Reflections 3. Using a Kenwood TS-830S I measured the parameters required to prove the output source resistance of the tank circuit of its RF power amp is non- dissipative. The measurements also prove that the reflected power incident on its output is totally re-reflected. From reading an earlier post of yours, Richard, I know you have read this portion of Chapter 19, and you agreed with it. My measured data conflicts with Best's Eq 8, so there's got to be a valid answer to this dilemma, but where? Walt Hi Walt, Yes, I am very familiar with your bench work. *I am very annoyed by those who trivialize it. *I am further annoyed by those who patronize you to then shift the parameters to explain something else - completely abandoning you. However, I also acknowledge that I can hurt your feelings about where I stand on these matters. *Yes, to a limited degree, I do agree with much of your assessment, but I do not follow it into the arena of where you express it as being "non-dissipative." * However, my denying this proposition does NOT mean I dispute your other proposition of complete reflection. *This cross connection of several topics is where things get overly complex and gives the entire discussion the appearance of a house of cards. I cannot tell what your agenda is, but the material you quote as source, and for which I have provided links to in this thread - all seem a subtext to non-dissipative sources. *Attention directed towards this pursuit of matching points rendered in stubs seems like tea leaf reading to resolve a larger issue. As a student, tech, and engineer employing a LOT of precision waveguide technology, I am quite comfortable with the components and topologies you describe. *Arguments for wave interferences being rendered into useful circuit constructs (that is, constructed on the basis of wave interference) has been with us easily since the early 40s. *One component, the ATR tube, is one I have handled and replaced to insure the proper operation of RF paths being steered in waveguides. *One proviso, however = for any of these "virtualizations" to work, they require a physical (and dissipative) element as the initiator. *Waves do not interfere without the presence of a physical element (often some form of detector, or minimally a load). 73's Richard Clark, KB7QHC Thanks again Richard, for your insightful response. And goodness no, Richard, you won't hurt my feelings. I like being correct, but if I'm not I surely want to be told about it. This situation is no different. However, if you're not following me on the 'non-dissipative' path, I'd like you to review the last portion of the TS-830S experiment, and follow the numbers. If you don't have that material in front of you, you can find it again on my web page at www.w2du.com. Click on 'Preview Chapters from Reflections 3', and then click on Chapter 19A, which is a part of Chapter 19 in the 3rd edition. Observe that when the load impedance is changed from 50+j0 to the complex impedance 17.98 + j8.77 ohms, the plate current rose expectedly from 260ma to 290ma. This change occurred because the amp is now mismatched, and the pi-network is also detuned from resonance. The unwashed would conclude that the reflected power caused the increase in plate current. However, one will also observe that after the pi-network has been retuned and adjusted to again deliver all the available power into the otherwise 'mismatched' load (which is now matched to the source), the plate current went back to it's original value, 260ma. In addition, the amp returned to deliver 100w into the complex impedance at the line input, with the 30.6w of reflected power in the line, and adding to the 100w of source power, making 130.6w incident on the mismatched load, absorbing 100w and reflecting 30.6w. IMHO, these data prove beyond doubt that the pi-network not only didn't absorb any of the reflected power, but totally re-reflected it. In my book this says the pi-network reflection coefficient rho = 1.0. How can anyone disagree with this? Walt |
#3
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On Tue, 14 Jun 2011 14:18:53 -0700 (PDT), walt wrote:
Thanks again Richard, for your insightful response. And goodness no, Richard, you won't hurt my feelings. I like being correct, but if I'm not I surely want to be told about it. This situation is no different. However, if you're not following me on the 'non-dissipative' path, I'd like you to review the last portion of the TS-830S experiment, and follow the numbers. If you don't have that material in front of you, you can find it again on my web page at www.w2du.com. Click on 'Preview Chapters from Reflections 3', and then click on Chapter 19A, which is a part of Chapter 19 in the 3rd edition. Observe that when the load impedance is changed from 50+j0 to the complex impedance 17.98 + j8.77 ohms, the plate current rose expectedly from 260ma to 290ma. This change occurred because the amp is now mismatched, and the pi-network is also detuned from resonance. The unwashed would conclude that the reflected power caused the increase in plate current. However, one will also observe that after the pi-network has been retuned and adjusted to again deliver all the available power into the otherwise 'mismatched' load (which is now matched to the source), the plate current went back to it's original value, 260ma. In addition, the amp returned to deliver 100w into the complex impedance at the line input, with the 30.6w of reflected power in the line, and adding to the 100w of source power, making 130.6w incident on the mismatched load, absorbing 100w and reflecting 30.6w. Hi Walt, There is absolutely NOTHING that I can dispute in your numbers or method. However, as to "dissipation" this says nothing. As for what it says about the reflection coefficient, I would agree with you. However, the math and the math experts you speak of - they are not answering the model we are examining above. You distracted them with stubs and reflecting waves. If you cast this agreement in the reflection coefficient back into effects purported to exist in the matching with stubs model, we may yet argue. IMHO, these data prove beyond doubt that the pi-network not only didn't absorb any of the reflected power, but totally re-reflected it. In my book this says the pi-network reflection coefficient rho = 1.0. How can anyone disagree with this? *** Nothing further useful about the topic is to be found below *** There is a curious side bar to this found at: http://www.w5big.com/purchase4170c.htm Observe the second data screen that purports to examine a mismatch through a length of both RG58 and RG59 terminated with 100 Ohms. Of particular note is the distinct transition from the Zc of 50 Ohms to the Zc of 75 Ohms and the similarly distinct transition from the Zc of 75 Ohms to the termination R of 100 Ohms. Note that the transitions both span a distance of 2 feet. 2 feet is not insubstantial compared to connection technology that spans, probably, no more than one tenth that distance. Whence the extra 11 inches on both sides of the connection plane of either connection? In the physics I've been studying for the past 10 years, near fields, this would not be unusual. In fact it would be expected. There is a transition zone (in waveguide design, there would be a taper or a sweep section to anticipate this and they would be physically large in terms of wavelength) not a transition cliff. Similarly, at the connector to your TS-830S, there is a zone that surrounds it that only approximates the 50 Ohm which occurs (in the terms of this link's demonstration) some distance away, deep inside your TS-830S. To me, dissipation inhabits this zone (certainly large enough for the tube and tank to occupy) and embraces the match with a complex addition of phases that could result in loss or even gain. This is also to say that I do not subscribe to dissipation being all about loss - especially when the hand of man is on the tuning knob instead of letting the chips fall where they may. 73's Richard Clark, KB7QHC |
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