|
Loading Coils; was : Vincent antenna
On Thu, 06 Dec 2007 21:22:09 GMT, Cecil Moore
wrote: Based on your questions, an ordinary prudent man would assume that you are just wasting my time. Next thing is that you will be ragging on me for the number of postings I had to make in answering your questions. Well, you didn't answer them all did you? And you didn't really have anything to show short of those answers until I asked for them, did you? And you certainly don't have a page of published RESULTs such as Tom has where the settings and readings are all readily visible and available, do you? Of course this laborious, tedious, and painstaking. This is called the work of science and engineering - or you could just go back to mooching for validation, the correspondence you commit to that in a hour far exceeds responding to these few questions over several days. So, what voltage magnitudes were presented to the inputs of your scope? or should I consider your silence to a rather ordinary question as you having hit the limit of your technical depth? |
Loading Coils; was : Vincent antenna
Dave Heil wrote:
... "John", I'm sorry you're having difficulties in making it more simple. So you'd have me believe that you're a MENSA member? Do you attend under your pseudonym? Did you, by the way, mean "principles" or did you really intend the word "principals"? That's very "strang". Dave K8MN Dave: The word is "transparent", you neighbors, you family members know--attend a self-help group ... it may help others around you. JS |
Loading Coils; was : Vincent antenna
On Thu, 06 Dec 2007 21:33:20 GMT, Cecil Moore
wrote: Richard Clark wrote: It would be intriguing to discover how your rig drove 5W through the coil to a 48:1 mismatch. I already reported more than a year ago that it was through an autotransformer. I matched the coil Z0 on both the source end and the load end. So what was the windings ratio? 73's Richard Clark, KB7QHC |
Loading Coils; was : Vincent antenna
On Thu, 06 Dec 2007 21:33:20 GMT, Cecil Moore
wrote: Richard Clark wrote: It would be intriguing to discover how your rig drove 5W through the coil to a 48:1 mismatch. I already reported more than a year ago that it was through an autotransformer. I matched the coil Z0 on both the source end and the load end. Did you take the input to Channel 1 from this autotransformer? |
Loading Coils; was : Vincent antenna
John Smith wrote:
Dave Heil wrote: ... "John", I'm sorry you're having difficulties in making it more simple. So you'd have me believe that you're a MENSA member? Do you attend under your pseudonym? Did you, by the way, mean "principles" or did you really intend the word "principals"? That's very "strang". Dave K8MN Dave: The word is "transparent"... Fine. I've changed your sentence to read: "Means it is acknowledgment of the worth of transparent, practices and knowledge ..." you neighbors, you family members know--... Me neighbors and me family members will think it reads awfully funny. ...attend a self-help group ... it may help others around you. No thanks, John. If you're an example of what self-help groups have done, I believe I'll give it a pass. If I had to venture a guess, I'd guess you're the wrong guy to explain what goes on at a MENSA meeting. Dave K8MN |
Loading Coils; was : Vincent antenna
Dave Heil wrote:
... Dave K8MN Dave: You remind me of a fellow in the neighborhood when I was a kid, used to go around talking to himself all the time ... no one paid him much attention, nowadays would be different of course. :-) JS |
Loading Coils; was : Vincent antenna
AI4QJ wrote:
"Cecil Moore" wrote in message . net... AI4QJ wrote: Going further, I am still trying to consider how the extra angle can also be absorbed "into" an impedance discontinuity. I have started a phasor diagram of it but it is not finished yet. Maybe a Smith Chart explanation will work. All lines are lossless. On a Smith Chart normalized to 100 ohms, lay out the 10 degrees of 100 ohm line from the infinity point, i.e. the open-circuit point. The reactance value is tan(90-10) = 5.67. That means the reactance value is 5.67*100 = -j567 ohms which has to be the value at the impedance discontinuity. Now on a Smith Chart normalized to 600 ohms, lay out the x degrees of 600 ohm line from the zero point to the point where -j567/600 is located. Read the number of degrees required. It is Arctan(567/600) which is equal to ~43 degrees. The phase shift at the impedance discontinuity is therefore 90-10-43 = 37 degrees. I think I see why it no longer surprizes me after going through the smith chart. The 100 ohm line (10 degrees) is open. The 600 ohm line has a load impedance of -j567 ohms, it is not open. The fact that it is terminated with an impedance (the 100 ohm line) adds degrees on the chart. We should expect the reactance of the 100 ohm line to add phase angle at the termination similar to a "discreet component". Hope this makes sense; the smith chart makes it very clear. Do you want to work that out mathematically? 73, Tom Donaly, KA6RUH |
Loading Coils; was : Vincent antenna
Gene Fuller wrote:
Cecil Moore wrote: AI4QJ wrote: ... it is plain and simple "intuitive" once you know that current changes along the electrical "degree length" in an unloaded antenna, the same should happen in the degree length loaded coil. Unfortunately, both sides cannot be right but both sides are still illustrated as fact in the ARRL Antenna Book. There's one graphic that shows the drop in amplitude through a loading coil and another that shows no change. Apparently, the ARRL doesn't know what happens so they show both possibilities as technically correct. Every author has a problem in drawing those diagrams, because we are trying to draw too many things at the same time: physical height, electrical height, loading coils, current distributions and voltage distributions. It doesn't matter which viewpoint we are trying to illustrate, it is still impossible to draw *all* of those things truthfully to scale on the same diagram. When comparing the full quarter-wave against the mobile whip, we have to choose: do we draw the two antennas to true physical scale; or do we use an 'electrical' scale of 0 to 90deg? Whichever one we choose, the scale for the other on becomes grossly distorted, and this is what leads to confusion. Every author has trouble with this. Illustrations by different authors attempt to square the circle in different ways, but none of them ever can succeed because it fundamentally cannot be done. ARRL publications are no exception, and a further complication is that the handbook compilations tend to re-use illustrations from individual articles by different authors. So please don't read too much into the mixture of drawing styles - the reasons are often more historical than technical. Also, as indicated, the pictures do say 1000 words and it also looks like W8JI ended up agreeing with you after you pointed out the same effect at "ON4UN's Low Band DXing", 3rd Edition, on page 9-34. Unfortunately, it is rumored that W8JI has talked ON4UN into changing that in the latest edition. I emailed ON4UN about it but got no reply. It has been changed. There is no longer any discussion of "degrees", only "current". Well, not quite. The 4th edition does use degrees for the electrical lengths of the plain unloaded sections (which is valid from everyone's point of view); but it no longer implies that the loading coil "replaces" any number of degrees. I don't know the detailed history behind that change, but I do know one thing: ON4UN is not a man to be swayed by "political" influence. The change in the 4th edition would be because he was challenged to look again at the *technical* issues, and then he made up his own mind. -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
Loading Coils; was : Vincent antenna
On Dec 6, 1:23 pm, Cecil Moore wrote:
Keith Dysart wrote: You should also consider a shortened monopole where lumped elements are used to tune out the reactance. Please feel free to pursue that line of development if you are so inclined. Since lumped elements do not exist in reality, they are outside of the scope of real-world 75m mobile loading coils that I am trying to cover here. I am not proposing a theory of everything nor do I intend to waste my time with such. But be my guest. You have done this before; postulating explanations that only work in the complexity of the "real" world, but fail when presented with the simplicity of ideal test cases. Then, when the explanations fail on the simple cases, claiming these cases are not of interest because the real world is more complex. It won't fly. Good explanations also work when presented with test cases from the simpler world of ideal components. ....Keith |
Loading Coils; was : Vincent antenna
Dave Heil wrote:
Where's the fulfillment in standing around in a room full of folks congratulating each other on how smart they are? It gets the females turned on. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
AI4QJ wrote:
I think I see why it no longer surprizes me after going through the smith chart. The 100 ohm line (10 degrees) is open. The 600 ohm line has a load impedance of -j567 ohms, it is not open. The fact that it is terminated with an impedance (the 100 ohm line) adds degrees on the chart. We should expect the reactance of the 100 ohm line to add phase angle at the termination similar to a "discreet component". Hope this makes sense; the smith chart makes it very clear. ---43.4 deg 600 ohm line---+---10 deg 100 ohm line---open The Smith Chart does make it clear what is happening. Here is the math to go with it. The impedance at the junction of the two lines is: -j100*tan(90-10) = -j100*tan(80) = -j567 ohms -j600*tan(43.4) = -j600*tan(43.4) = -j567 ohms The phase shift at the junction of the two lines is: 80-43.4 = 36.6 degrees Time permitting, I will work up the phasor diagrams of the component voltages (or currents) at the junction where rho = (600-100)/(600+100) = 0.7143 -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Richard Clark wrote:
On Thu, 06 Dec 2007 21:22:09 GMT, Cecil Moore wrote: Based on your questions, an ordinary prudent man would assume that you are just wasting my time. Next thing is that you will be ragging on me for the number of postings I had to make in answering your questions. Well, you didn't answer them all did you? I answered them until the total number of them started approaching infinity when your motive became clear. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
So, what voltage magnitudes were presented to the inputs of your
scope? |
Loading Coils; was : Vincent antenna
On Dec 7, 11:21 am, Cecil Moore wrote:
---43.4 deg 600 ohm line---+---10 deg 100 ohm line---open The Smith Chart does make it clear what is happening. Here is the math to go with it. The impedance at the junction of the two lines is: -j100*tan(90-10) = -j100*tan(80) = -j567 ohms -j600*tan(43.4) = -j600*tan(43.4) = -j567 ohms The phase shift at the junction of the two lines is: 80-43.4 = 36.6 degrees Time permitting, I will work up the phasor diagrams of the component voltages (or currents) at the junction where rho = (600-100)/(600+100) = 0.7143 If the 100 ohm line was only 5 degrees long, how long would the 600 ohm line have to be to obtain 0 ohms at the input? Would the phase shift at the junction still be 36.6 degrees? ....Keith |
Loading Coils; was : Vincent antenna
Tom Donaly wrote:
I think I see why it no longer surprizes me after going through the smith chart. The 100 ohm line (10 degrees) is open. The 600 ohm line has a load impedance of -j567 ohms, it is not open. The fact that it is terminated with an impedance (the 100 ohm line) adds degrees on the chart. We should expect the reactance of the 100 ohm line to add phase angle at the termination similar to a "discreet component". Hope this makes sense; the smith chart makes it very clear. Do you want to work that out mathematically? For the stub to be electrically 1/4WL, the following must hold where L1 and L2 are in degrees. -jZ01*tan(L1) = -jZ02*cot(L2) = -jZ02*tan(90-L2) -j600*tan(43.4) = -j100*cot(10) = -j567 ohms at the junction When L1 = L2, the stub is half Z01 and half Z02. Such a stub is very close to 1/2 the physical length of a single-Z0 stub when Z01/Z02 = 6. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Ian White GM3SEK wrote:
The 4th edition does use degrees for the electrical lengths of the plain unloaded sections (which is valid from everyone's point of view); but it no longer implies that the loading coil "replaces" any number of degrees. "Replace" seems to mean different things to different people so it is not a good word to use without a stated definition. It would probably be better to say the loading coil "occupies" a certain number of degrees in a loaded antenna. The number of degrees occupied by the coil varies but it is in the tens of degrees for a 75m mobile loading coil. Here is an EXCEL file that computes the Z0 and VF of a loading coil assuming it meets the "less than 1" test included in the computation. Of course, the results are only approximate since some secondary effects, such as wire diameter, are ignored. http://www.w5dxp.com/CoilZ0VF.xls The VF of a 75m Texas Bugcatcher coil is ~0.02 at 4 MHz. Since it is ~7 inches long, it occupies ~43 degrees of antenna. The stinger occupies ~10 degrees so the coil indeed does not "replace" 80 degrees of antenna. It *occupies* 43 degrees of the antenna. The rest of the necessary phase shift, 90-43-10 = 37 degrees, occurs at the coil to stinger impedance discontinuity where the Z0 of the coil is ~4000 ohms and the Z0 of the stinger is ~400 ohms. A 10/1 ratio of Z0s causes a considerable phase shift in the traveling waves, not in the standing- waves. One side of the argument recognizes only the phase shift through the coil. The other side of the argument recognizes only the phase shift at the top of the coil. Both sides are partially right and partially wrong. Interestingly, the truth lies just about half way in between the two rail arguments. About half of the "missing degrees" are contributed by the part of the antenna *occupied* by the coil while the rest is contributed by the impedance discontinuity between the coil and the stinger. I don't know the detailed history behind that change, but I do know one thing: ON4UN is not a man to be swayed by "political" influence. The change in the 4th edition would be because he was challenged to look again at the *technical* issues, and then he made up his own mind. If he changed his mind based on experiments using standing- wave current measurements, he is still wrong. I have tried to contact him using his ARRL email address, but got no reply. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Keith Dysart wrote:
You have done this before; postulating explanations that only work in the complexity of the "real" world, but fail when presented with the simplicity of ideal test cases. For Pete's sake, Keith, Ohm's law doesn't even work when R=0. Then, when the explanations fail on the simple cases, claiming these cases are not of interest because the real world is more complex. I define the boundary conditions within which my ideas work. Whether they work outside those defined conditions is irrelevant. I believe they do work for ideal conditions, but I don't have the need to prove a "theory of everything". Every model that we use has flaws. Asking me to come up with a flawless "theory of everything" model is an obvious, ridiculous diversion but you already know that. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Keith Dysart wrote:
If the 100 ohm line was only 5 degrees long, how long would the 600 ohm line have to be to obtain 0 ohms at the input? -jcot(5) = -j11.43 normalized to Z0=100 ohms -j100(11.43) = -j1143 ohms at the junction -j1143/600 = -j1.905 normalized to Z0=600 ohms arctan(1.905) = 62.3 degrees of Z0=600 ohm line Would the phase shift at the junction still be 36.6 degrees? The new phase shift would be 90-5-62.3 = 22.7 deg. 62.3 + 5 + 22.7 = 90 degrees This example would correspond to a larger coil and a shorter stinger in a loaded mobile antenna. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Cecil Moore wrote:
... It gets the females turned on. ROFLOL! My gawd man, you must be a riot at a party! Regards, JS |
Loading Coils; was : Vincent antenna
On Dec 7, 1:00 pm, Cecil Moore wrote:
Keith Dysart wrote: If the 100 ohm line was only 5 degrees long, how long would the 600 ohm line have to be to obtain 0 ohms at the input? -jcot(5) = -j11.43 normalized to Z0=100 ohms -j100(11.43) = -j1143 ohms at the junction -j1143/600 = -j1.905 normalized to Z0=600 ohms arctan(1.905) = 62.3 degrees of Z0=600 ohm line Would the phase shift at the junction still be 36.6 degrees? The new phase shift would be 90-5-62.3 = 22.7 deg. 62.3 + 5 + 22.7 = 90 degrees This example would correspond to a larger coil and a shorter stinger in a loaded mobile antenna. -- 73, Cecil http://www.w5dxp.com The smith chart shows this well. If I go up only 5 degrees on the outer circle of open-end (infinite impedance on the 100 ohm line), lower values of electrical angle corresponds to higher reactance, in this case -j1143 for the 5 degree line instead of -j567 for the 10 degree line at the junction. The new phase shift at the junction should be, and is, now lower since the 100 ohm line has a higher capacitive reactance at the junction. As the 100 ohm line is shortened to 0 degrees, we have a 600 ohm transmission line that is open and now the 600 ohm line must be lengthened to the full 90 degrees for 1/4W. This would correspond to a coil with no stinger. |
Loading Coils; was : Vincent antenna
On Dec 7, 3:02 pm, wrote:
On Dec 7, 1:00 pm, Cecil Moore wrote: Keith Dysart wrote: If the 100 ohm line was only 5 degrees long, how long would the 600 ohm line have to be to obtain 0 ohms at the input? -jcot(5) = -j11.43 normalized to Z0=100 ohms -j100(11.43) = -j1143 ohms at the junction -j1143/600 = -j1.905 normalized to Z0=600 ohms arctan(1.905) = 62.3 degrees of Z0=600 ohm line Would the phase shift at the junction still be 36.6 degrees? The new phase shift would be 90-5-62.3 = 22.7 deg. 62.3 + 5 + 22.7 = 90 degrees This example would correspond to a larger coil and a shorter stinger in a loaded mobile antenna. -- 73, Cecil http://www.w5dxp.com The smith chart shows this well. If I go up only 5 degrees on the outer circle of open-end (infinite impedance on the 100 ohm line), lower values of electrical angle corresponds to higher reactance, in this case -j1143 for the 5 degree line instead of -j567 for the 10 degree line at the junction. The new phase shift at the junction should be, and is, now lower since the 100 ohm line has a higher capacitive reactance at the junction. As the 100 ohm line is shortened to 0 degrees, we have a 600 ohm transmission line that is open and now the 600 ohm line must be lengthened to the full 90 degrees for 1/4W. This would correspond to a coil with no stinger.- Hide quoted text - - Show quoted text - Ooops, I am posting from the web. This is AI4QJ. |
Loading Coils; was : Vincent antenna
On Dec 7, 1:00 pm, Cecil Moore wrote:
Keith Dysart wrote: If the 100 ohm line was only 5 degrees long, how long would the 600 ohm line have to be to obtain 0 ohms at the input? -jcot(5) = -j11.43 normalized to Z0=100 ohms -j100(11.43) = -j1143 ohms at the junction -j1143/600 = -j1.905 normalized to Z0=600 ohms arctan(1.905) = 62.3 degrees of Z0=600 ohm line Would the phase shift at the junction still be 36.6 degrees? The new phase shift would be 90-5-62.3 = 22.7 deg. 62.3 + 5 + 22.7 = 90 degrees So sometimes a 600 to 100 ohm discontinuity produces a 36.6 degree phase shift and sometimes it produces a 22.7 degree phase shift (and probably any value in between). I suggest that "work[ing] up the phasor diagrams of the component voltages (or currents) at the junction where rho = (600-100)/(600+100) = 0.7143" will not be useful for predicting the phase shift. ....Keith |
Loading Coils; was : Vincent antenna
On Dec 7, 12:46 pm, Cecil Moore wrote:
Keith Dysart wrote: You have done this before; postulating explanations that only work in the complexity of the "real" world, but fail when presented with the simplicity of ideal test cases. For Pete's sake, Keith, Ohm's law doesn't even work when R=0. A rather large red herring. Ideal components are the topic, and we mostly use ideal wire with R=0 without difficulty. Then, when the explanations fail on the simple cases, claiming these cases are not of interest because the real world is more complex. I define the boundary conditions within which my ideas work. Whether they work outside those defined conditions is irrelevant. I believe they do work for ideal conditions, but I don't have the need to prove a "theory of everything". Sounds good, but mostly you do not examine ideal conditions because they tend to show that the models fail. With non-ideal conditions, the discussion is easy to drive far from the target and prevent resolution of whether the model works. ....Keith |
Loading Coils; was : Vincent antenna
Tom Donaly wrote:
Mike Coslo wrote: "Mike Kaliski" wrote in I went along to a couple of meetings many years ago. Full of under achievers with high IQ's complaining how they weren't being recognised or credited in their exams/career/promotion ladder/etc. Intelligence is like talent. It is a gift. What you do with it is what is important. Just because you have one or the other is almost irrelevant if you don't have the other tools needed to be sucessful. I feel like such a piker here - I'm only 150........ - 73 de Mike N3LI - That's o.k. It just means you think less like Terman than some of the others in this group do. I was a little shocked to read his bio. - 73 de Mike N3LI - |
Loading Coils; was : Vincent antenna
Keith Dysart wrote:
Sounds good, but mostly you do not examine ideal conditions because they tend to show that the models fail. With non-ideal conditions, the discussion is easy to drive far from the target and prevent resolution of whether the model works. My postulate is that Newton was wrong: moving objects come to a rest without any external applied force. Every observation made supports this. There's no need to consider what happens in a frictionless environment, since such a thing doesn't exist. Roy Lewallen, W7EL |
Loading Coils; was : Vincent antenna
On Dec 7, 3:05 pm, Keith Dysart wrote:
On Dec 7, 1:00 pm, Cecil Moore wrote: Keith Dysart wrote: If the 100 ohm line was only 5 degrees long, how long would the 600 ohm line have to be to obtain 0 ohms at the input? -jcot(5) = -j11.43 normalized to Z0=100 ohms -j100(11.43) = -j1143 ohms at the junction -j1143/600 = -j1.905 normalized to Z0=600 ohms arctan(1.905) = 62.3 degrees of Z0=600 ohm line Would the phase shift at the junction still be 36.6 degrees? The new phase shift would be 90-5-62.3 = 22.7 deg. 62.3 + 5 + 22.7 = 90 degrees So sometimes a 600 to 100 ohm discontinuity produces a 36.6 degree phase shift and sometimes it produces a 22.7 degree phase shift (and probably any value in between). That's right, depending on the electrical (and physical) length of the 100 ohm line, it will have different values of reactance as seen by the 600 ohm line, therefore different phase shifts, all the way to zero when the length of the 100 ohm line is 0 degrees and the reactance is infinite (the 600 ohm line sees an open circuit). Say at 0+ degrees, -jX(C) = 1000000000; this is where you see it headed when you look at the smith chart. At zero degrees of 100 ohm line, you have 90-0-90 = 0 degrees at the discontinuity. AI4QJ |
Loading Coils; was : Vincent antenna
Dave Heil wrote:
Mike Coslo wrote: "Mike Kaliski" wrote in I went along to a couple of meetings many years ago. Full of under achievers with high IQ's complaining how they weren't being recognised or credited in their exams/career/promotion ladder/etc. Intelligence is like talent. It is a gift. It can be more like a curse. There's nothing quite like a number of teachers telling Junior's parents that Junior is gifted. What you do with it is what is important. Just because you have one or the other is almost irrelevant if you don't have the other tools needed to be sucessful. I feel like such a piker here - I'm only 150........ You don't look that old, Mike. I would be younger, but I was sick a lot as a kid.... - 73 de Mike N3LI - |
Loading Coils; was : Vincent antenna
Dave Heil wrote:
Mike Coslo wrote: "Mike Kaliski" wrote in I went along to a couple of meetings many years ago. Full of under achievers with high IQ's complaining how they weren't being recognised or credited in their exams/career/promotion ladder/etc. Intelligence is like talent. It is a gift. It can be more like a curse. There's nothing quite like a number of teachers telling Junior's parents that Junior is gifted. Little Mikey just doesn't apply himself..... Little Mikey was bored, but that would mean it was their fault Oops sorry about that - it was a thrid grade flashback 8^) - 73 de Mike N3LI - |
Loading Coils; was : Vincent antenna
|
Loading Coils; was : Vincent antenna
Cecil Moore wrote:
Dave Heil wrote: Where's the fulfillment in standing around in a room full of folks congratulating each other on how smart they are? It gets the females turned on. It is a well know scientific fact the only true aphrodisiac is a man doing housework. - 73 de Mike N3LI - |
Loading Coils; was : Vincent antenna
Keith Dysart wrote:
So sometimes a 600 to 100 ohm discontinuity produces a 36.6 degree phase shift and sometimes it produces a 22.7 degree phase shift (and probably any value in between). Yes, of course - nobody said the phase shift wasn't a variable. Why would you expect it to be a constant? It is a variable that depends upon the phase of the component forward and reflected waves. I suggest that "work[ing] up the phasor diagrams of the component voltages (or currents) at the junction where rho = (600-100)/(600+100) = 0.7143" will not be useful for predicting the phase shift. It will be useful for reporting that particular phase shift. If other conditions change, that phase shift will change. What is unexpected about that? -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Keith Dysart wrote:
Sounds good, but mostly you do not examine ideal conditions because they tend to show that the models fail. I believe that is a false statement. Please prove your assertion. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
Roy Lewallen wrote:
My postulate is that Newton was wrong: moving objects come to a rest without any external applied force. Every observation made supports this. There's no need to consider what happens in a frictionless environment, since such a thing doesn't exist. There seems no limit to which you will go to protect your old wives' tales. How about taking a look at the EZNEC file at: http://www.w5dxp.com/coil512.ez and commenting on the results. Nobody is going to hold his breath while you make up your mind. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
John Smith wrote:
Dave Heil wrote: ... Dave K8MN Dave: You remind me of a fellow in the neighborhood when I was a kid, used to go around talking to himself all the time ... no one paid him much attention, nowadays would be different of course. :-) We'll never know to what you refer, "John". You snipped it. Look, you're already using a pseudonym, why not just admit that you're that kid you mentioned? If you're accusing me of talking to myself, walk through the scenario. You made a newsgroup response to one of my posts. I responded to you. You responded to me. I responded to you. It is apparent that I'm not talking to myself. Dave K8MN |
Loading Coils; was : Vincent antenna
Cecil Moore wrote: Jim Kelley wrote: What does "its current maximum is not caused by standing waves" mean to someone with an "IQ of 168"? I explained it already. The current maximum in a loading coil is caused by the magnetic flux linkage between the adjacent coils. Yes, you did say that, but it isn't apparent to me that the two statements are necessarily mutually exclusive. To me those things are all interdependent. Insofar as constructive interference is caused by reflections from discontinuities and not the other way around, then yes. But the current maximum is simply an area of constructive interference. It is the profile of a standing wave in 2 dimensions caused by the superposition of forward and reflected waves. The phase and amplitude of the forward and reflected waves are of course determined by the nature of the line, and those parameters determine the profile of the standing wave. It is the same thing that approximately doubles the velocity factor of the coil over what it would be if the all the current followed the wire. I think current is required to follow the wire in any case. :-) 73, Jim AC6XG |
Loading Coils; was : Vincent antenna
Jim Kelley wrote:
Cecil Moore wrote: I explained it already. The current maximum in a loading coil is caused by the magnetic flux linkage between the adjacent coils. Yes, you did say that, but it isn't apparent to me that the two statements are necessarily mutually exclusive. The distance between current anti-nodes is 180 degrees. All the lack of apparentness in the world will not change that fact of physics. -- 73, Cecil http://www.w5dxp.com |
Loading Coils; was : Vincent antenna
On 7 Dec, 12:24, Roy Lewallen wrote:
Keith Dysart wrote: Sounds good, but mostly you do not examine ideal conditions because they tend to show that the models fail. With non-ideal conditions, the discussion is easy to drive far from the target and prevent resolution of whether the model works. My postulate is that Newton was wrong: moving objects come to a rest without any external applied force. Every observation made supports this. There's no need to consider what happens in a frictionless environment, since such a thing doesn't exist. Roy Lewallen, W7EL Wrong.. When you are beyond the confines of all gravitational fields and in a state of equilibrium then there can not be friction. Somebody somewhere has obviously postulated that gravitational forces are every where which puts science back in the stone ages. Sure messes up Gauss and quite a few others. In fact the law of statics is based on gravitational field which extends to what Gauss called the limits of gravitational effects. Quite a few other laws are based on similar logic Art Unwin KB9MZ.....XG(uk) |
Loading Coils; was : Vincent antenna
Cecil Moore wrote:
The distance between current anti-nodes is 180 degrees. Such insight is incredible to behold. ac6xg |
Loading Coils; was : Vincent antenna
art wrote:
Wrong.. When you are beyond the confines of all gravitational fields and in a state of equilibrium then there can not be friction. Somebody somewhere has obviously postulated that gravitational forces are every where which puts science back in the stone ages. Sure messes up Gauss and quite a few others. In fact the law of statics is based on gravitational field which extends to what Gauss called the limits of gravitational effects. Quite a few other laws are based on similar logic Art Unwin KB9MZ.....XG(uk) That has got to be the worst logic I have EVER heard and flies in the face of common sense to be unspeakable--Roys' comment. An object in motion, with NO external forces HAS to continue to move with exactly the same stored energy as it began with, even a trillion years later ... Logic asks: Where would the stored energy go? Imparted to nothing? Just disappears--breaking all the laws dealing with the conservation of energy also? Art, give up, we are in the twilight zone, look for an exit! However, an ABSOLUTE frictionless environment may be quite difficult to come up with ... Regards, JS |
Loading Coils; was : Vincent antenna
Dave Heil wrote:
... Dave K8MN Dave: While your statements are quite well constructed to inflame and insult a child--that has to do with your mind, not my age ... ROFLOL! JS |
| All times are GMT +1. The time now is 04:26 AM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com