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Loading Coils; was : Vincent antenna
Roy Lewallen wrote:
This is simply a diversion to deflect the discussion away from the sticky questions about "electrical degrees" which his theory is unable to resolve. Phase reference is another, and we can expect more. There were no black boxes in the original example so the black box was the original diversion. Coming back from that diversion, can you calculate the current amplitude and phases in the original example? I would be very surprised if you could do it. I would be even more surprised if you did it and published the results. Roy, here's your chance to nail me to the wall. Simply prove that the phase shift between Vfor1 and Vfor2 below is something other than 36.6 degrees. (All of Roy's worshipers hold their breath for a response. :-) This is not "my" theory - this is standard distributed network reflection theory that I learned at Texas A&M in the 50's. And the theory is certainly capable of resolving the electrical degree problems. Here's the original example again - no black box necessary. --43.4 deg 600 ohm line--+--10 deg 100 ohm line--open Vfor1--|--Vfor2 Assuming 100v at 0 deg incident upon the open at the end of the stub, what is the phase shift between Vfor1 and Vfor2? Vfor2 = 100v at -10 deg Vfor1 = 143.33v at -46.4 deg The phase shift between Vfor1 and Vfor2 is 36.6 degrees just as predicted originally. Roy, you are always advising me to use voltages so I did. The results are easy to verify if you know how. But I don't think you know how. Everyone is invited to use any valid model you want to and prove me either right or wrong. I predict that Roy will be silent on this subject and rely on his political power to try to suppress those results. The emperor has no clothes. The emperor's worshipers have no clothes. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
"Gene Fuller" wrote in message ... Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: keep going guys! only 50 more messages to hit 1000 in this thread! thats got to be a record for r.r.a.a! how many more ways can cecil and roy go around in circles with phases. can we get roger back in the fray? that would be good for another dozen or so anyway! jim lux hasn't contributed recently, where did he drop out? and where, oh where, is art?????????? |
Loading Coils; was : Vincent antenna
Dave wrote:
how many more ways can cecil and roy go around in circles with phases. For a guru like Roy, it should be easy to nail me to the wall with a few calculations. But have you noticed the complete absence of math and equations from Roy to prove me wrong? One wonders why all he does is kibitz with ad hominem attacks. -- 73, Cecil http://www.w5dxp.com |
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Dave wrote:
"Gene Fuller" wrote in message ... Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: keep going guys! only 50 more messages to hit 1000 in this thread! thats got to be a record for r.r.a.a! how many more ways can cecil and roy go around in circles with phases. can we get roger back in the fray? that would be good for another dozen or so anyway! jim lux hasn't contributed recently, where did he drop out? and where, oh where, is art?????????? And then there is anonymous Dave, who never contributes anything useful. |
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Cecil Moore wrote:
Gene Fuller wrote: If the antenna current was referenced to the source current, the reported antenna current phase would *not* change when the source phase was changed. This gives a whole new meaning to "referenced". The antenna currents are phase-locked to the source current. That's about as good a reference as one can get - being phase-locked. You, like Richard C., are obviously just pulling my leg. Sleep on it. You may feel better in the morning. |
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Dave wrote:
"Gene Fuller" wrote in message ... Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: keep going guys! only 50 more messages to hit 1000 in this thread! thats got to be a record for r.r.a.a! how many more ways can cecil and roy go around in circles with phases. can we get roger back in the fray? that would be good for another dozen or so anyway! jim lux hasn't contributed recently, where did he drop out? and where, oh where, is art?????????? Aw, shaddup! This thread hasn't even gotten started yet. Tom Donaly, KA6RUH |
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Cecil Moore wrote:
But the rules for black boxes do not allow measurements on the inside. This is how they help clarify the thinking. So instead of sweeping technical facts under the rug, you hide them in a black box. In both cases, the only apparent purpose is to maintain ignorance. It seems that whatever part of the system you don't understand, you draw a black box around it so you don't have to understand it. No, it is a perfectly normal technique to test a theory or model. The black box reveals just enough information to solve the problem, and nothing more. In this particular case, the impedance at the terminals of the black box is the only *necessary* information to solve the transmission-line problem (in the steady state, at one frequency). It is not necessary to know how that impedance was created. Conventional transmission-line theory handles this situation effortlessly, thus proving that no more information is needed. Any theory that claims to need more information has failed the test - for somewhere it has a soft centre that means it cannot be trusted. Professional scientists and engineers are quite ruthless about this. They don't wait for other people to propose such tests - they do it themselves, beating hardest on their own ideas, to find out what they're good for and where the limits are. Any ideas that don't stand up to this treatment are ruthlessly discarded. That isn't always easy, but a professional scientist or engineer has to have the clarity and integrity to know when it has to be done. That is why the professionals are very careful not to keep ideas as pets. As in farming, it's only the amateurs who can afford that self-indulgence. -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
Loading Coils; was : Vincent antenna
On Dec 19, 3:32 pm, Cecil Moore wrote:
Gene Fuller wrote: If the antenna current was referenced to the source current, the reported antenna current phase would *not* change when the source phase was changed. This gives a whole new meaning to "referenced". The antenna currents are phase-locked to the source current. That's about as good a reference as one can get - being phase-locked. You, like Richard C., are obviously just pulling my leg. Try a non-electronic example. If all the dimensions on my house are referenced to the left front corner, when I move the left front corner (along with the rest of the house), none of the numerical values change. If the dimensions are referenced to the fire hydrant, all the measurements change by the same amount after the move. This is your opportunity to demonstrate that you are not like your "gurus" who never admit mistakes. Or we could have a fun discussion about Mulroney who recently said ""The most difficult thing in life, I think, is to admit one's mistakes . . . ". Clearly Mulroney is not like the rest of us who make enough mistakes that we have plenty of practice admitting them. Oh wait. Maybe he makes them, but just refuses to admit them. Hmmmm. ....Keith |
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Ian White GM3SEK wrote:
In this particular case, the impedance at the terminals of the black box is the only *necessary* information to solve the transmission-line problem (in the steady state, at one frequency). It is not necessary to know how that impedance was created. Black boxes have their function but I doubt that any proponent of black boxes will admit that the function proposed here is to obscure technical facts because those technical facts are distasteful to some people. Ian, the entire problem (as stated previously by me) is to ascertain the phase shift at the impedance discontinuity between Vfor1 in the 600 ohm line and Vfor2 in the 100 ohm line at point '+' in the following example. That is the problem as stated. It's a straight forward problem - no black box necessary. --43.4 deg 600 ohm line--+--10 deg 100 ohm line--open Vfor1--|--Vfor2 Assuming the voltage incident upon the open end of the stub is 100 volts at 0 degrees, I calculate the following voltages at point '+'. Vfor2 = 100 volts at -10 degrees Vfor1 = 143.33 volts at -46.6 degrees The phase shift between Vfor1 and Vfor2 is 36.6 degrees. You should be able to prove or disprove those values. In fact, you seem to be frothing at the mouth wanting to disprove them. Well, go ahead and prove me wrong (if you can). Instead of performing the calculations to disprove my figures, you attempt to sweep part of the problem under the rug by putting everything from point '+' to the end of the stub in a black box thus making the stated problem impossible to solve. I'm sorry, but that is an unethical diversion away from the stated problem. I have already stated that no matter what is in the black box, if the impedance or impedor is -j567 then the conditions external to the black box are identical. But that diversion has nothing to do with solving the original problem. Why are you afraid to solve the problem as stated? I am going to keep repeating this posting until someone provides a solution to the original problem. My voltage calculations above are either right or wrong. If they are wrong, as you suggest, please prove it. If they are right, I don't blame you for trying your best to suppress the technical facts by hiding things in a black box but now the whole world is aware of your attempted suppression of technical facts, not a good reputation to have for a technical editor. -- 73, Cecil http://www.w5dxp.com |
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Keith Dysart wrote:
Try a non-electronic example. OK, what is the *reference interest rate* for an adjustable rate mortgage? An ever changing prime rate? References do not have to be fixed. I was using the EZNEC source current as the reference. I rarely ever change that current away from the default value of 1 amp at 0 degrees. This is your opportunity to demonstrate that you are not like your "gurus" who never admit mistakes. I freely admit that the definition of "reference" that I was using is different from the definition that others could choose. It was a mistake not to better define the word before I used it. However, I did state that I was using the EZNEC default current as my reference and nobody objected to that statement at the time. -- 73, Cecil http://www.w5dxp.com |
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Dave wrote:
keep going guys! only 50 more messages to hit 1000 in this thread! thats got to be a record for r.r.a.a! how many more ways can cecil and roy go around in circles with phases. can we get roger back in the fray? that would be good for another dozen or so anyway! jim lux hasn't contributed recently, where did he drop out? and where, oh where, is art?????????? Just a phase they are going through............. - 73 d eMike N3LI - |
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Michael Coslo wrote:
Just a phase they are going through............. Exactly what is the reference for that phase? :-) -- 73, Cecil http://www.w5dxp.com |
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On Dec 20, 11:02 am, Cecil Moore wrote:
Michael Coslo wrote: Just a phase they are going through............. Exactly what is the reference for that phase? :-) Fire hydrant. ------------------- 35 messages to go. |
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Keith Dysart wrote:
On Dec 20, 11:02 am, Cecil Moore wrote: Michael Coslo wrote: Just a phase they are going through............. Exactly what is the reference for that phase? :-) Fire hydrant. Hey Keith, have you been able to disprove my figures in my other thread "Please verify (or disprove)"? If not, why not? Seems it would be an ideal time to nail me to the wall with some math that disagrees with mine. -- 73, Cecil http://www.w5dxp.com |
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Tom Donaly wrote:
jim lux hasn't contributed recently, where did he drop out? Nothing really to contribute.. Jim,w6rmk |
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Jim Lux wrote:
Tom Donaly wrote: jim lux hasn't contributed recently, where did he drop out? Nothing really to contribute.. Jim, would you please check my math in the thread titled, "Please verify (or disprove)"? Appreciate it. -- 73, Cecil http://www.w5dxp.com |
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Cecil Moore wrote:
I don't blame you for trying your best to suppress the technical facts by hiding things in a black box If that is what you wish to believe, then there is no way to convince you otherwise. but now the whole world is aware of your attempted suppression of technical facts, not a good reputation to have for a technical editor. So you accuse; but I'm content to let everyone else be the judge. -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
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On Dec 20, 4:32 am, Ian White GM3SEK wrote:
Cecil Moore wrote: But the rules for black boxes do not allow measurements on the inside. This is how they help clarify the thinking. So instead of sweeping technical facts under the rug, you hide them in a black box. In both cases, the only apparent purpose is to maintain ignorance. It seems that whatever part of the system you don't understand, you draw a black box around it so you don't have to understand it. No, it is a perfectly normal technique to test a theory or model. The black box reveals just enough information to solve the problem, and nothing more. In this particular case, the impedance at the terminals of the black box is the only *necessary* information to solve the transmission-line problem (in the steady state, at one frequency). It is not necessary to know how that impedance was created. But Ian, Suppose the box is labeled -j567 ohms. Then I ask, "at what frequency is this impedance -j567?". I find that the impedance for -j567 ohms is 4 Mhz. Now I take a length of 600 ohm VF = 1 transmission line and vary the length until I am at resonance with whatever is in the black box at 4 MHz. Resonance would imply 90 degrees total phase shift. My measurement shows that the length of 600 ohm line to cause this effect is 43 degrees. Assuming my measurement is correct, doesn't that tell us a little more about what is inside the box? It isn't just "any" -j567 ohm impedance that can cause resonance with a 43 degree 600 ohm line. It is probably not a discreet capacitor, it would likely be some sort of transmission line or something that that has 10 deg length, correct? With a few more measurements, we can determine the Zo of the transmission line that "appears' to be in the black box, correct and essentially verify that it a transmission line. We should be able to both measure and calculate Zo. If we choose our independent measurements carefully enough, we should be able to define exactly what is in the black box with only 2 terminals. I agree you need more than a smith chart (which was where I made my mistake before). AI4QJ |
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Ian White GM3SEK wrote:
Cecil Moore wrote: I don't blame you for trying your best to suppress the technical facts by hiding things in a black box If that is what you wish to believe, then there is no way to convince you otherwise. It's not what I believe, Ian, it is what you did right here in front of God and everybody. There was absolutely no reason to introduce a black box concept unless you were trying to hide something embarrassing inside the black box. That embarrassing something is obviously the phase shift at an impedance discontinuity which you are trying your best to suppress. but now the whole world is aware of your attempted suppression of technical facts, not a good reputation to have for a technical editor. So you accuse; but I'm content to let everyone else be the judge. If you aren't trying to suppress technical facts, then please perform the math on my other thread, "Please verify (or disprove)" and post your results whether or not they agree with my results. By refusing to respond, you will be enforcing my worst fears about your ulterior motives, i.e. to suppress the technical facts about that phase shift. -- 73, Cecil http://www.w5dxp.com |
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Jim Lux wrote:
Tom Donaly wrote: jim lux hasn't contributed recently, where did he drop out? Nothing really to contribute.. Jim,w6rmk I didn't write that, Dave did. 73, Tom Donaly, KA6RUH |
Loading Coils; was : Vincent antenna
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Loading Coils; was : Vincent antenna
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Loading Coils; was : Vincent antenna
Roy Lewallen wrote:
Gene is of course correct. Perhaps the difficulty with basic concepts such as phase reference is part of the reason why Cecil finds it necessary to invent and promote his alternative theories. A moment's thought would reveal one good reason not to reference phase angles to "the source" -- NEC and EZNEC allow multiple sources, each having a phase angle chosen by the user. Roy Lewallen, W7EL Hello, Roy and all. Every unmoderated science newsgroup I've lurked in always has one or more individuals that seem to delight in bucking conventional science wisdom even in those cases where experimental evidence completely validates the predictions of applied mathematics. (Gosh, what ever happened to cold fusion?) One guy regularly complains that respected physics journals won't publish his papers. Of course he imagines there's someone or some agency out to get him, never considering other reasons for his rejection. Perhaps on usenet he acquires some validation. Hey, people are free to view nature and its processes however they choose but if they want others to view it that way it takes more than "Because I say so." Especially to a roomful of skeptics. Of course I'm also reminded of the hornet's nest that Marilyn vos Savant stirred up a few years back in academia with the "Monty Hall" problem. (Turned out she was right after all) The truth always emerges eventually. Theories often have to be modified as new discoveries occur. Are you sure I can't interest you in an energy-saving power factor correction capacitor for your home/ham shack? How about a broadband dipole with a feedpoint VSWR 1.6 over the contiguous 2-30 MHz band? Sincerely, and 73s N4GGO, |
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J.B. Wood wrote:
Roy Lewallen wrote: Gene is of course correct. Perhaps the difficulty with basic concepts such as phase reference is part of the reason why Cecil finds it necessary to invent and promote his alternative theories. A moment's thought would reveal one good reason not to reference phase angles to "the source" -- NEC and EZNEC allow multiple sources, each having a phase angle chosen by the user. Hello, Roy and all. Every unmoderated science newsgroup I've lurked in always has one or more individuals that seem to delight in bucking conventional science wisdom even in those cases where experimental evidence completely validates the predictions of applied mathematics. On this newsgroup, John, it's the gurus who are bucking conventional science with such concepts as: 1. There's no phase shift at a Z01 to Z02 impedance discontinuity in a transmission line even though the applied mathematics says there is. Black boxes are quickly introduced to hide the phase shift from the unwashed masses. 2. There's no difference between I*cos(kx)*cos(wt) and I*cos(kx+wt) i.e. between standing waves and traveling waves even though the applied mathematics graphs are completely different. 3. Standing wave current can be used to measure the delay through a loading coil even though applied mathematics says the standing wave current doesn't change its relative phase anywhere in the 1/4WL antenna from feedpoint to tip. 4. Reflected waves contain zero energy and therefore cannot deliver energy back to the source even though applied mathematics says that ExB is the power density of that reflected wave. 5. EM energy can just "slosh around" inside a transmission line. It doesn't have to travel at the speed of light even though it is made up of photons which applied mathematics tells us cannot slow down. 6. The EZNEC graph of traveling-wave current phase contains a 64% error yet the author says there's nothing wrong. John, would you care to comment on those six points? -- 73, Cecil http://www.w5dxp.com |
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Cecil Moore wrote:
6. The EZNEC graph of traveling-wave current phase contains a 64% error yet the author says there's nothing wrong. Oops, sorry, should be (100-64) = 36% error. -- 73, Cecil http://www.w5dxp.com |
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Cecil Moore wrote:
a 64% error yet the author says there's nothing wrong. John, would you care to comment on those six points? Hello, Cecil, and I think Roy and others have provided valid comment. I would like to recommend, in addition to the ARRL publications, the Schaum's Outline on transmission lines. I don't know if it's still in print but it was authored by Chipman. Like the other paperback Schaum's Outlines it is not intended to be an in-depth examination of RF transmission line theory (if you want that I would recommend King and Harrison's book). Chipman's book, OTOH delves into the theory at a level that IMHO doesn't require an EE degree to comprehend. There's also loads of practical problems worked out (lots of stuff on incident, reflected and standing waves). I think it would prove timely to pursue sources besides r.r.a.a for your electromagnetics training. Sincerely, |
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"Gene Fuller" wrote in message ... Dave wrote: "Gene Fuller" wrote in message ... Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: Cecil Moore wrote: Gene Fuller wrote: keep going guys! only 50 more messages to hit 1000 in this thread! thats got to be a record for r.r.a.a! how many more ways can cecil and roy go around in circles with phases. can we get roger back in the fray? that would be good for another dozen or so anyway! jim lux hasn't contributed recently, where did he drop out? and where, oh where, is art?????????? And then there is anonymous Dave, who never contributes anything useful. i gave up trying to be helpful in these endless arguments long ago. i went through trying to be helpful by pointing out the inconsistencies, then when i realized that they wouldn't listen i slipped into trolling them just to watch the fun, and now i'm just jabbing them like a hornet nest. LESS THAN 20 TO GO TO HIT 1000!!!! |
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J.B. Wood wrote:
Hello, Cecil, and I think Roy and others have provided valid comment. I would like to recommend, in addition to the ARRL publications, the Schaum's Outline on transmission lines. I don't know if it's still in print but it was authored by Chipman. Like the other paperback Schaum's Outlines it is not intended to be an in-depth examination of RF transmission line theory (if you want that I would recommend King and Harrison's book). Chipman's book, OTOH delves into the theory at a level that IMHO doesn't require an EE degree to comprehend. There's also loads of practical problems worked out (lots of stuff on incident, reflected and standing waves). I think it would prove timely to pursue sources besides r.r.a.a for your electromagnetics training. Sincerely, Bob, I've had the book for 30+ years. I'm not kidding about those six items. Those are the old wives' tales being spread by about six of the gurus on this newsgroup. I learned this fields and waves stuff back in the 50s from Ramo, Whinnery, and Johnson and some good professors at Texas A&M. In particular, how about taking a look at my math on the thread titled "Please verify (or disprove)". I would welcome anyone proving me wrong but so far, there are zero takers. -- 73, Cecil http://www.w5dxp.com |
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wrote in message ... On Dec 20, 4:32 am, Ian White GM3SEK wrote: Cecil Moore wrote: But the rules for black boxes do not allow measurements on the inside. This is how they help clarify the thinking. So instead of sweeping technical facts under the rug, you hide them in a black box. In both cases, the only apparent purpose is to maintain ignorance. It seems that whatever part of the system you don't understand, you draw a black box around it so you don't have to understand it. No, it is a perfectly normal technique to test a theory or model. The black box reveals just enough information to solve the problem, and nothing more. In this particular case, the impedance at the terminals of the black box is the only *necessary* information to solve the transmission-line problem (in the steady state, at one frequency). It is not necessary to know how that impedance was created. But Ian, Suppose the box is labeled -j567 ohms. Then I ask, "at what frequency is this impedance -j567?". I find that the impedance for -j567 ohms is 4 Mhz. Now I take a length of 600 ohm VF = 1 transmission line and vary the length until I am at resonance with whatever is in the black box at 4 MHz. Resonance would imply 90 degrees total phase shift. My measurement shows that the length of 600 ohm line to cause this effect is 43 degrees. Assuming my measurement is correct, doesn't that tell us a little more about what is inside the box? It isn't just "any" -j567 ohm impedance that can cause resonance with a 43 degree 600 ohm line. It is probably not a discreet capacitor, it would likely be some sort of transmission line or something that that has 10 deg length, correct? With a few more measurements, we can determine the Zo of the transmission line that "appears' to be in the black box, correct and essentially verify that it a transmission line. We should be able to both measure and calculate Zo. If we choose our independent measurements carefully enough, we should be able to define exactly what is in the black box with only 2 terminals. I agree you need more than a smith chart (which was where I made my mistake before). AI4QJ No, you can't. if the frequency is fixed, is sinusoidal, and steady state, then every box that measures -j567 ohms is perfectly equal. that is the whole idea of a 'black box' not only can't you tell what is inside, it doesn't matter what you do on the outside, it will always looks the same. that is the whole purpose of it, you reduce a part of the circuit to a single component that has well known performance so you remove that part from the problem. |
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J.B. Wood wrote:
Cecil Moore wrote: a 64% error yet the author says there's nothing wrong. John, would you care to comment on those six points? Hello, Cecil, and I think Roy and others have provided valid comment. BTW, the current plotting error in EZNEC is (100-64) = 36%. Do you think a 36% plotting error within EZNEC is nothing to worry about? Do you think when current phase is displayed as a sine wave instead of a straight line, that is OK? -- 73, Cecil http://www.w5dxp.com |
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Dave wrote:
if the frequency is fixed, is sinusoidal, and steady state, then every box that measures -j567 ohms is perfectly equal. If the goal is to measure the phase shift at an impedance discontinuity in a transmission line, why would someone deliberately put the impedance discontinuity inside a black box? That defeats the goal of measuring the phase shift. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
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Loading Coils; was : Vincent antenna
Roy Lewallen wrote:
Let me reiterate that the contents of the boxes can certainly be distinguished with tests made at multiple frequencies. But the objective of my comments has been to counter the claim that there's some terminal property such as "electrical degrees" which the various lines (box contents) have which is different at the single frequency at which their reactances are the same. I hear this claim still being made, but so far not any evidence to support it. I provided the evidence in the thread titled, "Please verify (or disprove)". You have yet to respond to it. Here's your chance to nail me to the wall for good, Roy. Why are you so silent on that thread? -- 73, Cecil http://www.w5dxp.com |
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On Thu, 20 Dec 2007 18:21:28 -0600, Cecil Moore
wrote: Why Everyone knows "why" but you, apparently. This has been explained many times, and quite clearly with a very simple explanation. No theory is involved, no proofs required, no data needs to be offered, a simple statement has resolved "why" a loooooooong time ago. Ask "why" again. Confirm the stereotype and pick up the doorprize. ;-) |
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Roy Lewallen wrote:
When such evidence (not including typical Cecil-style hand-waving, but real numbers) is presented, I'll be glad to point out where it's in error. OK Roy, here's your chance. From the previous example: --43.4 deg 600 ohm line--+--10 deg 100 ohm line--open Vfor1--|--Vfor2 Vf--| Vref1--|--Vref2 Vr--| Given Vf = 100 volts at 0 deg. Vfor2 = 100 volts at -10 deg Vref2 = 100 volts at +10 deg Vfor2 = tau1*Vfor1 + rho2*Vref2 = 100 volts at -19 deg Solving for Vfor1 = 143.33 volts at -46.6 degrees Vref1 = rho1*Vfor1 + tau2*Vref2 = 143.33 volts at +46.6 deg Note that the two above equations are equivalent to the s-parameter equations: b1 = s11*a1 + s12*a2 and b2 = s21*a1 + s22*a2 -- 73, Cecil http://www.w5dxp.com |
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Cecil Moore wrote:
Vfor2 = tau1*Vfor1 + rho2*Vref2 = 100 volts at -19 deg Obvious Typo: should be 100 volts at -10 deg -- 73, Cecil http://www.w5dxp.com |
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AI4QJ wrote:
"Cecil Moore" wrote in message ... wrote: It isn't just "any" -j567 ohm impedance that can cause resonance with a 43 degree 600 ohm line. Dan, I believe you will find that any -j567 impedance in the black box will put the forward and reflected waves back in phase, i.e. resonant. OK but if you can measure Zo of whatever is in the box, then you know the length by virtue of it being -j567. It should only take 2 terminals to measure Zo. Knowing Zo, then I can normalize the smith chart and directly read the electrical length in degrees. True, it would help to know that the box contains a transmission line. The "other side" will not allow you to assume a transmission line. The "other side" will not even allow you four terminals on your black box. The entire purpose of the black box, in this present context, is to confuse and confound the unwashed masses so the "other side" can maintain their guru status. -- 73, Cecil http://www.w5dxp.com |
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On Dec 20, 11:35*am, Cecil Moore wrote:
Keith Dysart wrote: On Dec 20, 11:02 am, Cecil Moore wrote: Michael Coslo wrote: Just a phase they are going through............. Exactly what is the reference for that phase? :-) Fire hydrant. Hey Keith, have you been able to disprove my figures in my other thread "Please verify (or disprove)"? If not, why not? Seems it would be an ideal time to nail me to the wall with some math that disagrees with mine. Your math is typically fine (although you messed up big time with your use of "reference"), when you allow yourself to use it. It is the interpretations, conclusions, and allocations of importance that are flawed. But now that you have declared black boxes a conspiracy to hide "the facts", I'm thinking maybe you should go join the MI5 guy. Anyway, along the way you learned (or maybe already knew and just articulated) that the effect on the 600 ohm line is the same regardless of the content of the black box producing -j567, and for the black boxes, the phase shift at the terminals is undecidable. And since the problem can be solved without this information, it is also irrelevant. A bit of progress. ...Keith 8 to go. |
Loading Coils; was : Vincent antenna
Keith Dysart wrote:
Your math is typically fine ... Aha, so you agree that there is a 36.6 degree phase shift between Vfor1 and Vfor2? That is certainly progress. Now if you can only convince the gurus. But now that you have declared black boxes a conspiracy to hide "the facts", I'm thinking maybe you should go join the MI5 guy. I didn't say all black boxes are a conspiracy to hide the facts. But consider that when the goal is to measure the phase shift at an impedance discontinuity and someone insists on putting the impedance discontinuity inside a black box where the phase shift cannot possibly be measured, then that person desperately wants to keep the results from that measurement from being known. Anyway, along the way you learned (or maybe already knew and just articulated) that the effect on the 600 ohm line is the same regardless of the content of the black box producing -j567, There was never any argument there so that statement is just a straw man - go ahead and knock it down and get it over with. Nobody disagrees with you. and for the black boxes, the phase shift at the terminals is undecidable. And since the problem can be solved without this information, it is also irrelevant. The phase shift at the impedance discontinuity *CANNOT* be solved without information about the impedance discontinuity. Exactly what is it that you are so afraid that someone is going to discover? The technical facts? You already admitted that my calculations were accurate and valid. What more could you possibly want to hide? -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
On Thu, 20 Dec 2007 21:09:53 -0500, "AI4QJ" wrote:
But I am only trying to find out what is in the box so it is a mental exercize. Hi Dan, Then you have missed the entire point. I know it is a transmission line, open, and the impedance at 4MHz is -j567. You know? Then why try to find out? This is a contradiction on the face of it. And what if it is not what you know it to be, and it still presents -j567 at 4MHz? If Zo for example were 100 Ohms, then -j567 would correspond to -j5.67 on a smith chart normalized to 100 ohms and it is 10 degrees long. If indeed! What electrical length corresponds to -j567 if Zo measures 200 ohms? 300 ohms? They will all be different right? Of course, any one of an infinite number of different possible contents could reside within the box; but you don't know which one is inside the box unless you look. This reminds me of an argument I had with a Chief Boatswain's Mate when I challenged him that "you can't make a horse drink water." His (like Cecil's) solution was: "You hold his head under water and suck on his ass!" I hear this particular solution has been used to solve an unrelated problem: a way of curing chapped lips (it keeps you from licking them). The better part of the members here use chapstick. 73's Richard Clark, KB7QHC |
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