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Current across the antenna loading coil - from scratch
Gene Fuller wrote:
... one value for the motion of a particle ... Now I know you are pulling our legs. We are talking about *electrons*, Gene, you know that "particle" capable of going through two slits at the same time and interferring with itself on the other side? Please pick out just one electron and tell us what is its position and velocity. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
Why didn't you set us straight about 3000 messages ago? If only we knew that RF current was a mere artifact we could have shortened this thread to one message. Well Gene, that fact didn't occur to me 3000 messages ago so I recently corrected my mistaken concepts. What do you do when you discover a mistaken concept of your own? (rhetorical question) Truth is, I'm still learning. How about you? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Gene Fuller wrote: So you think adding turns to a coil is a nice linear process that allows you to then subdivide the resonance effects according the number of turns in each subsection? That appears to me to be the most valid measurement that we can make of the delay through a coil. If you have a better way, please present it. Cecil, C'mon, you know as well as anybody that inductance of a coil tends to increase as n-squared. Yes, there are all kinds of special cases and correction factors. Adding turns and then pretending everything is nice and linear, thereby allowing decomposition into subcomponents, is just plain silly. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
Cecil, can I infer from your reply that you, too, can't find anything
in W8JI's original posting that refers to a lumped model? With respect to your request, I suggest you re-read Tom's whole posting and see if you can understand it. W8JI should perhaps have included in the statement you quoted, "in and of itself/themselves," but certainly it's accurate in the context from which you've extracted it. Certainly you can have "current taper" along an antenna or along a TEM transmission line for reasons other than loss to radiation or heating, and ALL of them go right back to the very basics of what's going on in an antenna and in a transmission line, and what Maxwell et al were explaining with all their work. Cheers, Tom Cecil wrote, in a posting for which the Usenet ID is available on request, K7ITM wrote: Could you please enlighten us, Cecil, exactly why you think that anything in all of W8JI's full posting referenced by reference below where he implicitly or explicitly says anything at all about a lumped model, or about lumped behaviour? After a careful search, I'm unable to find it. I only find a discussion of distributed behaviour in a circuit which extends beyond near field. W8JI is right 99% of the time. I agree with him on those things as do you. Your above posting is no surprise. Here's one of W8JI's statements. Please defend it. W8JI said: Radiation does not cause current taper. Dissipation does not either. What is contained in the attenuation factor for the current transmission line equation if not radiation and dissipation? What else is there? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Richard Harrison wrote:
Gene, W4SZ wrote: "However, the physical entities do not have two values at once in the same time and place." You can measure each of the two simultaneous constituents with the right equipment. A Bird Thruline wattmeter uses a directional coupler to separate forward direction power from reverse direction power. These are obbtainable at the same time and place anywhere in a 50-ohm coax line. Individual volts and amps in each direction are easily calcuable from the powers indicated in each direction. Best regards, Richard Harrison, KB5WZI Richard, You are in luck! This is Burger King day. Have it your way. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
David G. Nagel wrote: Tom Have you ever sloshed water in a bowl? If you had you would have seen wave forms going in both directions. First the initial wave crosses the bowl then reflects off the side of the bowl and returns in the opposite direction. This is the same as an EMF wave in an antenna. No violation of any principles of conservation, in fact it is demanded of the principle. Dave WD9BDZ Dave, You have highlighted a misconception that is common and a great cause of confusion in this forum. Yes, the "waves" can do what you say. However, the "waves" are merely mathematical descriptions of the underlying physical phenomena. There is simply no such thing as a "wave" all by itself. Instead there are water waves, electromagnetic field waves, guitar string waves, sound waves, and so on. Nature tends to be single valued, at least in the ordinary classical world. At any specific point in time and space there is only one value of current, one value of electric field, one value for the motion of a particle (water molecule, guitar string molecule, etc.), one charge density, and so on. These values can and do change with differences in time and space. However, the physical entities do not have two values at once in the same time and place. 73, Gene W4SZ Now if we can only convince certain other individuals of this maybe we can get back to something useful, such as how many angles can dance on the head of a pin. Dave WD9BDZ |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Gene Fuller wrote: ... one value for the motion of a particle ... Now I know you are pulling our legs. We are talking about *electrons*, Gene, you know that "particle" capable of going through two slits at the same time and interferring with itself on the other side? Please pick out just one electron and tell us what is its position and velocity. Cecil, I think I specifically mentioned the "ordinary classical world", but I'll play along. Why don't you go ahead and measure that electron to prove that it goes through both slits at once? 8-) |
Current across the antenna loading coil - from scratch
Gene, W4SZ wroyte:
"However, the physical entities do not have two values at once in the same time and place." All that is needed to prove energy in the incident and reflected waves each has its own values is to separate the two with a directional coupler as the Bird Thruline wattmeter does. It gives you forward and reverse powers at the same place anywhere you choose along a transmission line. The standard device is calibrated for 50-ohm lines so it is easy to convert the power indicationsw to volts and amps if desired. Take what Tom, W8JI wrote today: "I take it you are saying you think current can flow in two directions at the same instant of time in a conductor, can be "lost" from a single conductor through radiation and resistance without a shunting impedance, conservation of chrge isn`t important and Maxwell`s equations are wrong." Of course, except for Maxwell! Maxwell`s equations work. Current can flow in opposite directions past a point. Shunting impedance makes a voltage divider with series impedance, but that`s not the only way to get a difference between points on a conductor or a coil. Conservation of charge isn`t an issue with r-f current in a wire or coil. Tom`s posting is nonsense. Best regards, Richard Harrison, KB5WZI |
Current across the antenna loading coil - from scratch
Cecil, WHAT is your hangup about "lumped-circuit"?? W8JI-Tom, Tom
Donaly, Ian White, Roy Lewallen, Gene Fuller, Reg Edwards, I, and others I can think of are NOT, repeat NOT, absolutely NOT, most definitely NOT, talking about a lumped-circuit model. A lumped-circuit model in general does NOT (repeat all the above emphasis) talk about individual charge carriers, and individual charge carriers are NOT required to talk about all the things we've been saying. Egad, man. I will repeat, Maxwell et al were working to explain the forces acting on charge, and the response of charge to those forces: the motion of charge, the acceleration of charge, the accumulation of charge. Fields, both electric and magnetic, are simply a mathematical and useful way to represent the forces caused by all charges (in motion, accelerated, at rest) on all other charges in the universe. Sometimes fields as developed in classical electrodynamics fail to accurately represent our observed reality, but they are still useful in describing a great many of our everyday observations, and in solving many--essentially all--of our everyday antenna problems. I won't say it didn't happen at all, but I certainly can't recall in any of these "discussions" getting down to considering individual charged particles. We're dealing with effects accurately represented by charge expressed as a continuum, distributed over space, with abrupt boundaries at the edges of conductors assuming the forces aren't great enough to rip free charge loose from the wires and form corona. We are dealing with quanta in such overwhelmingly great numbers and such small energy per quanta that there's no point in discussing them as quantized charge or photons. No, we're dealing with a linear system that's sufficiently accurately represented by a set of differential equations that all get back eventually to the interaction of a continuous distribution of charge, not a "lumped circuit" OR individual charged particles, which are themselves very different thing, even though we know that our distribution of charge is made up of such particles when viewed on a fine enough scale. So, PLEASE wake up and quit trying to attribute this "lumped circuit" stuff, and the completely independent charge quantization stuff, to this discussion. It simply is NOT there. It is absolutely NOT the point of all this. Cheers, Tom Cecil wrote in a posting whose Usenet ID is available on request, K7ITM wrote: Understanding the congrence among many methods/theories is a very nice thing, for it gives one confidence that they are correct, and the ability to apply the one that's most convenient to any particular problem. I would not want to take away wave theory, or any other valid theory, from you; I would only ask that you better understand that your pet is not the ONLY valid explanation. The point is that in any disagreement between the lumped-circuit model and a properly applied distributed network model, the lumped-circuit model loses *EVERY* time since the lumped-circuit model is a *SUBSET* of the distributed network model. If your current charge concepts disagree with Maxwell's equations, Maxwell's equations win *EVERY* time. Maxwell's equations do not require individual charge carriers. They work just fine considering only fields in the aether. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
David G. Nagel wrote:
Tom Donaly wrote: Richard Harrison wrote: Tom, W8JI wrote: "I take it you are saying you think current can flow two directions at the same instant of time in a conductor through radiation and resistance without a shunting impedance, conservation of charge isn`t important, and Maxwell`s equarions are wrong." That`s the wrong take. Maxwell works for me even if there is no aether. Anntennas work in free space without a ground but it is hard to duplicate free space conditions at high and lower frequencies here on earth. Every standing-wave antenna has a reflection caused by an impedance discontinuity at wire`s end. At this point, a reflection begins its travel back toward the generator. By the time the reflection arrives at the generator, every point on the wire has current flowing in both directions simultaneously. No shunting capacitance to earth or anyplace else is needed to conserve charge. The wire is self-sufficient. Radiation resistance is a convenience defined as the resistance which if placed in series with an antenna would consume the same power that the antenna is radiating. At every point along an antenna with a reflection, current is flowing in two directions at the same time. Best regards, Richard Harrison, KB5WZI Completely wrong, as usual. There is nothing in the natural world that can double itself and go two opposite directions at the same time. In order to do so it would have to violate the principle of the conservaton of charge. At any instant, the charge at a point has to be going either one direction or another which you can confirm using the wave equation which Cecil doesn't understand any more than you do. Superposition is a fine principle, but like any intellectual tool it has to be understood to be used properly. 73, Tom Donaly, KA6RUH Tom Have you ever sloshed water in a bowl? If you had you would have seen wave forms going in both directions. First the initial wave crosses the bowl then reflects off the side of the bowl and returns in the opposite direction. This is the same as an EMF wave in an antenna. No violation of any principles of conservation, in fact it is demanded of the principle. Dave WD9BDZ Tell me which of the water molecules moved in two opposite directions at the same time. The waves can move through each other in opposite directions, but their combined influence is what moves the water molecules. There are not two separate sets of water molecules that flow in opposite directions, either. It's the combined total of forces that causes the movement of both charge and water. Two opposite movements of either charge or water are impossible. 73, Tom Donaly, KA6RUH |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Tom Donaly wrote: There is nothing in the natural world that can double itself and go two opposite directions at the same time. Seems your ignorance also extends to entangled particles? In order to do so it would have to violate the principle of the conservaton of charge. This is simply one more example of the seduction of other- wise intelligent people by the lumped-circuit model's unproven presuppositions. You are confusing charge with EM wave energy. If two EM light waves traveling in opposite directions can cause a standing wave in empty space, then so can two RF waves traveling in opposite directions in space or around a wire. There is no requirement for current at all. Current is a left over artifact from the DC model. In fact, it can be proven that virtually all of the energy (power) exists solely in the two EM waves surrounding the wire and virtually none in the conductor. All that is required for standing waves is E-fields and H-fields traveling in opposite directions WHETHER A WIRE EXISTS OR NOT. If everyone were using Maxwell's equations instead of flawed simplified models, none of this confusion would exist. All of the energy is in the waves and none in the current or voltage. After all, E x H is the *total power* in a wave. There is no extra energy left over to support voltage and current. Cecil, if you knew what you were talking about you might be dangerous. 73, Tom Donaly, KA6RUH |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Tom Donaly wrote: You still don't get it. And you still haven't posted any technical information to contradict the technical information that I am posting. One wonders why? Cecil, when you post some technical information I'll respond appropriately. 73, Tom Donaly, KA6RUH |
Current across the antenna loading coil - from scratch
"K7ITM" wrote W8JI-Tom, Tom Donaly, Ian White, Roy Lewallen, Gene Fuller, Reg Edwards, I, and others I can think of are NOT, repeat NOT, absolutely NOT, most definitely NOT, talking about a lumped-circuit model. ========================================== I do wish you would't take my name in vain about what I might have said or not said. I have in fact said little or nothing about lumped circuits or anything else in this stupid, ridiculous argument. Please don't drag me down to your level. ---- Reg Edwards. |
Current across the antenna loading coil - from scratch
A bit further to this:
What should I do when I find that Maxwell's equations do NOT accurately describe the observable situation, with observations that can be easily repeated with the same results each time? What should I do about the fact that charge is indeed quantized if I look at it finely enough? What should I do about the fact that radiation is quantized if I look at it finely enough? Maxwell's equations don't account for or allow for those effects, respectively. Yes, I certaily accept Maxwell's equations as adequate to describe what I'm likely to see in any ham antenna I deal with, but at the same time, I realize that they are not the final word. What I WOULD like to get back to here is that all the theory I listed in the posting which precipitated all this, from Maxwell to King and everything in between, all agrees with how charge DOES behave well enough to be very useful. It's those abstractions which have been proposed which do NOT line up with those theories very well at all that I want to weed out. I'm for sure not going to use them, and I'd prefer to educate others to avoid them as well. For anyone interested in looking them up, I believe it will be found that Maxwell's equations become very uninteresting if there is no charge and no motion of charge. Fields alone don't do it. It's those things--charge and motion of charge--embodied right there in the equations, that result in what we describe as fields around our transmtting antennas: electric, magnetic, and most interesting to us here, electromagnetic. And on the receiving end, it's the motion of charges in response to the fields that produce an interesting result. Reference: http://hyperphysics.phy-astr.gsu.edu...ric/maxeq.html Cheers, Tom Cecil wrote, in a closing paragraph of a posting whose Usenet ID is available on request, If your current charge concepts disagree with Maxwell's equations, Maxwell's equations win *EVERY* time. Maxwell's equations do not require individual charge carriers. They work just fine considering only fields in the aether. |
Current across the antenna loading coil - from scratch
In a posting with Message-ID:
.com, I wrote, among other things, "W8JI-Tom, Tom Donaly, Ian White, Roy Lewallen, Gene Fuller, Reg Edwards, I, and others I can think of are NOT, repeat NOT, absolutely NOT, most definitely NOT, talking about a lumped-circuit model." Belay that. It is not for me to say what others are talking about. I am sorry if any have taken it the wrong way. Please replace it with the more carefully worded paragraph below. Cheers, Tom I am absolutely certain that I infer from the recent postings in this thread and other related threads that W8JI-Tom, Tom Donaly, Ian White, Roy Lewallen, Gene Fuller, Reg Edwards and others I can think of are NOT, repeat NOT, absolutely NOT, most definitely NOT, talking about a lumped-circuit model. I know with equal certainty that I have not been, in any of my postings here. If what I have inferred is not what the original authors of those postings intended, I invite them to post whatever they wish to make more clear their intent or to expand on their previous posting(s). Obviously, they don't need my invitation to do so. If any of them does not wish their name associated with this thread, I invite them to quit posting to it and to revoke their earlier posts. Again, they obviously don't need my invitation to do so. |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
Cecil Moore wrote: Gene Fuller wrote: So you think adding turns to a coil is a nice linear process that allows you to then subdivide the resonance effects according the number of turns in each subsection? That appears to me to be the most valid measurement that we can make of the delay through a coil. If you have a better way, please present it. C'mon, you know as well as anybody that inductance of a coil tends to increase as n-squared. Yes, there are all kinds of special cases and correction factors. Increasing the length of a coil or transmission line doesn't change its velocity factor at a fixed frequency. Adding turns and then pretending everything is nice and linear, thereby allowing decomposition into subcomponents, is just plain silly. Velocity factor is *nice* and linear, i.e. it is constant. Please stop these diversions. I'm sure you are not that ignorant. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
K7ITM wrote:
So, PLEASE wake up and quit trying to attribute this "lumped circuit" stuff, and the completely independent charge quantization stuff, to this discussion. It simply is NOT there. It is absolutely NOT the point of all this. I agree so please tell that to everyone who is defending the lumped circuit presuppositions. One cannot use the presuppositions of the lumped circuit model to prove those same presuppositions!!! If your current charge concepts disagree with Maxwell's equations, Maxwell's equations win *EVERY* time. Maxwell's equations do not require individual charge carriers. They work just fine considering only fields in the aether. And PLEASE wake up and quit screwing up the attributions on this newsgroup. You didn't say the above! I said the above. Why do you deliberately falsify the attributions? Such is illegal in Texas. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Tom Donaly wrote:
Tell me which of the water molecules moved in two opposite directions at the same time. The waves can move through each other in opposite directions, but their combined influence is what moves the water molecules. There are not two separate sets of water molecules that flow in opposite directions, either. It's the combined total of forces that causes the movement of both charge and water. Two opposite movements of either charge or water are impossible. Nobody is arguing about that so it is obviously just a straw man. The real question is: Can two EM waves travel in opposite directions in free space or along a wire. The answer is YES!!! Standing waves can exist in free space or along a wire. To deny the existence of standing waves is ridiculous. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Tom Donaly wrote:
Cecil, when you post some technical information I'll respond appropriately. Here it is for the 20th time as reported by EZNEC. http://www.qsl.net/w5dxp/travstnd.GIF -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
K7ITM wrote:
What should I do when I find that Maxwell's equations do NOT accurately describe the observable situation, with observations that can be easily repeated with the same results each time? You should find out what is wrong with those observations. Therefore, you should find out what is wrong with W8JI's and W7EL's measurements. If your current charge concepts disagree with Maxwell's equations, Maxwell's equations win *EVERY* time. Maxwell's equations do not require individual charge carriers. They work just fine considering only fields in the aether. Please cease and desist from attributing my postings to you, Tom. Such is illegal in Texas and probably also illegal in your state. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Gene, W4SZ wrote: "However, the physical entities do not have two values at once in the same time and place." Richard Harrison wrote: You can measure each of the two simultaneous constituents with the right equipment. A Bird Thruline wattmeter uses a directional coupler to separate forward direction power from reverse direction power. These are obbtainable at the same time and place anywhere in a 50-ohm coax line. Individual volts and amps in each direction are easily calcuable from the powers indicated in each direction. That's not true. The directional coupler in a Bird meter samples the across vector (voltage) from a capacitive divider and adds it to a sample voltage of the through vector (current) from a current transformer in a predetermined ratio. After that sum, the output is rectified. I can place it in a system with NO standing waves and it will show standing waves. I can place it in a system with standing waves and have it show NO standing waves. It does not measure standing waves, it simply measures the ratio and phase of voltage and current at one point in the transmission line. There can NEVER be current flowing at that point in two directions at the same instant of time, and the Bird does not even contain a system that samples standing waves. Now I can build a piece of test gear that does directly read standing waves, but it requires a line sampling lwength of at least 1/4 wl. Such a device would be totally independent of the actual operating impedance, and could read either current or voltage. The Bird meter is NOT that type of unit. 73 Tom |
Current across the antenna loading coil - from scratch
Apparently the sentiment
On Mon, 10 Apr 2006 23:05:48 -0400, "Yuri Blanarovich" wrote: You don't want to explain W5DXP models and answer his questions. bears no correlation to On Tue, 11 Apr 2006 04:08:34 GMT, Cecil Moore wrote: BOTTOM LINE: Until you can prove that a mobile antenna is 90 degrees long, your argument is just another straw man. that is of any significance to "Current across the antenna loading coil - from scratch" |
Current across the antenna loading coil - from scratch
On Mon, 10 Apr 2006 16:04:56 -0400, Michael Coslo
wrote: Not that I could fan the flames any more anyhow, but just what was the original discussion about anyhow? Hmmm, Mike, I bet you didn't find a pony in that pile of "responses" did you? 73's Richard Clark, KB7QHC |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Gene Fuller wrote: (snip) C'mon, you know as well as anybody that inductance of a coil tends to increase as n-squared. Yes, there are all kinds of special cases and correction factors. Increasing the length of a coil or transmission line doesn't change its velocity factor at a fixed frequency. (snip) That is an interesting hypothesis. How would you go about testing its validity? (Have you heard of end effects?) |
Current across the antenna loading coil - from scratch
John Popelish wrote:
Cecil Moore wrote: Increasing the length of a coil or transmission line doesn't change its velocity factor at a fixed frequency. That is an interesting hypothesis. Since I know you are going to nit-pick that statement, I probably should add "appreciably" in front of "change". :-) How would you go about testing its validity? The velocity factor of a piece of transmission line doesn't change appreciably with length. The velocity factor of a straight wire doesn't change appreciably with length. I would think that a two wavelength coil would be approximately twice as long as a one wavelength coil which would be approximately twice as long as a 1/2 wavelength coil. The equation for the velocity factor of a coil depends upon: 1. The diameter of the coil 2. The number of turns per unit length 3. The frequency None of those factors are dependent upon the length of the coil. (Have you heard of end effects?) Of course, it's the 5% difference between 468/f and 492/f. I'm not talking super accuracy here - just better accuracy than anyone has yet measured. It is akin to your suggestion that a coil be installed between two current nodes and its number of degrees calculated from that. I will try to take that same coil that I have been talking about and use your suggestion to see how close the results are. However, I am preparing for a 6 state Harley road trip over the Easter holidays and will not be back until Monday. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
(snip) However, I am preparing for a 6 state Harley road trip over the Easter holidays and will not be back until Monday. I envy you. I haven't been on a decent motorcycle ride since my 12,000 mile loop from Virginia to Alaska, and back, in May, 2002. Kill a few bugs for me. |
Current across the antenna loading coil - from scratch
Tom, W8JI wrote:
"The directional coupler in a Bird meter samples the across vector (voltage) from a capacitive divider and adds it to a sample voltage of the through vector (current) from a current transformer in a predetermined ratio. That`s close. In the cartridges is a loop terminated in a diode. Capacitive coupling of the loop to the center conductor of the precision ccoax supplies the voltage sample. Inductive coupling of the loop supplies the current sample. I`ve described operation several times here and once in this thread, so I won`t repeat it. SWR is easy to get from the forward and reflected indications of the wattmeter. VSWR = 1 + sq.rt. (ref. PWR / for. PWR) Divided by 1 - sq.rt. (ref. PWR / for. PWR) Bird supplies a family of VSWR lines on a graph of forward power vs. reflected power for those who would avoid the calculation. They can also supply a slide-rule to do rhe same. Best regards, Richard Harrison, KB5WZI |
Current across the antenna loading coil - from scratch
Reg Edwards wrote:
"K7ITM" wrote W8JI-Tom, Tom Donaly, Ian White, Roy Lewallen, Gene Fuller, Reg Edwards, I, and others I can think of are NOT, repeat NOT, absolutely NOT, most definitely NOT, talking about a lumped-circuit model. ========================================== I do wish you would't take my name in vain about what I might have said or not said. I have in fact said little or nothing about lumped circuits or anything else in this stupid, ridiculous argument. Please don't drag me down to your level. ---- Reg Edwards. If the argument is that ridiculous, why do you continue to read it? 73, Tom Donaly, KA6RUH |
Current across the antenna loading coil - from scratch
Responding to no one in particular. This is starting to make me miss the shorter Fractenna threads. Phil, comeonback good buddy. |
Current across the antenna loading coil - from scratch
Yuri Blanarovich wrote:
Check my article that describes the controversy, shows some proof of reality and then efforts of the "gurus" to deny it and "reason" why it can't be so. http://www.k3bu.us/loadingcoils.htm The problem is that back in 1953 in QST article there was erroneous conclusion/statement made, which propagated through the books, until W9UCW measured the current across the loading coils and found that there is significant drop from one end to the other, and the rest is (ongoing) history Hmm, certainly it would seem to make sense that: The current in a typical loading coil in the shortened antennas drops across the coil roughly corresponding to the segment of the radiator it replaces. Quote from your page. I would not expect anything else. If the loading coil is making the antenna act like a physically longer antenna, other "qualities" of that simulation are likely to be similar. Is there a reason why the coil would *not* do this? - 73 de Mike KB3EIA - |
Current across the antenna loading coil - from scratch
Mike Coslo wrote:
Yuri Blanarovich wrote: Check my article that describes the controversy, shows some proof of reality and then efforts of the "gurus" to deny it and "reason" why it can't be so. http://www.k3bu.us/loadingcoils.htm The problem is that back in 1953 in QST article there was erroneous conclusion/statement made, which propagated through the books, until W9UCW measured the current across the loading coils and found that there is significant drop from one end to the other, and the rest is (ongoing) history Hmm, certainly it would seem to make sense that: The current in a typical loading coil in the shortened antennas drops across the coil roughly corresponding to the segment of the radiator it replaces. Quote from your page. I would not expect anything else. If the loading coil is making the antenna act like a physically longer antenna, other "qualities" of that simulation are likely to be similar. Is there a reason why the coil would *not* do this? Yes, many, and they've been discussed here at length. That this concept is wrong can and has been shown by theory, modeling, and measurement. I made and posted measurements on this newsgroup in November 2003 which demonstrated clearly that the presumption is false. The loading coil isn't making the antenna act like a physically longer antenna. In the extreme case of a physically short inductor at the feedpoint, it's simply modifying the feedpoint impedance and has no effect whatever on the antenna's radiation. As the inductor gets longer, it does become some part of the antenna, but adding an inductor which resonates, say, a 45 degree physical radiator doesn't make the antenna act like a 90 degree physical radiator. Roy Lewallen, W7EL |
Current across the antenna loading coil - from scratch
Wes Stewart wrote:
Responding to no one in particular. This is starting to make me miss the shorter Fractenna threads. Phil, comeonback good buddy. They certainly made more sense. Dave N |
Current across the antenna loading coil - from scratch
Richard Harrison wrote:
Tom, W8JI wrote: "The directional coupler in a Bird meter samples the across vector (voltage) from a capacitive divider and adds it to a sample voltage of the through vector (current) from a current transformer in a predetermined ratio. That`s close. In the cartridges is a loop terminated in a diode. Capacitive coupling of the loop to the center conductor of the precision ccoax supplies the voltage sample. Inductive coupling of the loop supplies the current sample. I`ve described operation several times here and once in this thread, so I won`t repeat it. We're all agreed on what happens with the Bird's sampling lines and detector. The only differences arise from each person's attempt to condense it all into a couple of sentences, and aren't worth arguing about. But Richard cuts it too short when he claims that: A Bird Thruline wattmeter uses a directional coupler to separate forward direction power from reverse direction power. That claim confuses two different things: what the line-loop-detector hardware physically *does*; and what the indicated results *mean*. The first of these is agreed; the second is not. The disagreement is entirely about the interpretation - in other words, it's about the theory about standing and travelling waves. Richard habitually misses out this step, which makes it look as if the Bird wattmeter "proves" the physical existence of forward and reverse travelling waves of power. It doesn't. Everything that you see printed on the Bird's meter scale, and in the Bird literature, represents that company's particular interpretation of theory about waves on transmission lines. The details of that theory are *not* agreed within this newsgroup, which means that - to some people - the two halves of Richard's claim do not join up. -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
Current across the antenna loading coil - from scratch
Mike Coslo wrote: Yuri Blanarovich wrote: The current in a typical loading coil in the shortened antennas drops across the coil roughly corresponding to the segment of the radiator it replaces. Quote from your page. I would not expect anything else. If the loading coil is making the antenna act like a physically longer antenna, other "qualities" of that simulation are likely to be similar. Is there a reason why the coil would *not* do this? - 73 de Mike KB3EIA - Every reason in the world. This misconception is EXACTLY what started this whole thing years ago. The loading coil doesn't "replace" missing electrical degrees, it primarily corrects power factor by compensating reactance. Anything else is generally secondary, and is related to flaws in the system rather than something necessary. That idea repeats one of the worse myths about loading coils. The truth is the loading inductor almost never has the same phase shift in current as the missing antenna area it replaces, and it almost never has the same "current drop". "Current drop" isn't even a good English description of what happens in any circuit. I can have an antenna of given dimensions with a loading coil at one fixed spot. The difference in current flowing into one end and out the other can go all over the place, depending only on the coil's physical design wity the antenna resonant on the same frequency. This happens ONLY by changing the coil. If I had a coil that was compact and not against the groundplane with low stray capacitance compared to the antenna area above the coil, current difference between each terminal or through the coil could be immeasurable with reasonably good instrumentation. Phase shift in current could also be nearly zero. None of this would be anywhere near the area the coil replaces. Without any change in anything except the coil, I could change all that. If I replaced the coil with a long stub or very large single turn, it would indeed act more like the antenna area it "replaces". The reason for this is the coil's capacitance to ground and capacitance to space around the antenna, NOT the electrical degrees it replaces and certainly not the standing waves. This all can and has been proven over and over again. The very few people offering the long drawn out arguments against this really are violating basic electrical laws of how systems really work, and enforcing the myth that a loading coil is so many electrical degrees long or that displacement currents are not at work and current magically vanishes, or magically flows two directions at the same time at one point in a conductor. A few people have taken the model of standing waves, not understood the limits or boundary conditions of that model, and thought it to be an actual literal description of what really is happening. They appear to actually think current can flow two directions at the same time at the same point. They somehow thing we can have charge drift velocity in two directions at the same instant of time at one point in a conductor, or that current can just vanish into thin air without actually being diverted through a second path. A few people have violated the rules of charge conservation, charge movement, and misapplied the concept of standing waves, but the single largest error is standing behind the myth or misconception that that loading coil somehow acts like the "missing area of antenna". 73 Tom |
Current across the antenna loading coil - from scratch
Roy Lewallen wrote:
Yes, many, and they've been discussed here at length. That this concept is wrong can and has been shown by theory, modeling, and measurement. I made and posted measurements on this newsgroup in November 2003 which demonstrated clearly that the presumption is false. By now, even you know that standing wave current phase is fixed and unchanging and that those delay measurements of yours are invalid whether made on a wire or on a coil. The loading coil isn't making the antenna act like a physically longer antenna. Of course not! The loading coil is making the antenna act like an electrically longer antenna by adding a phase shift through the coil. The electrical lengthening is what resonates the antenna feedpoint to a pure resistance. In the extreme case of a physically short inductor at the feedpoint, it's simply modifying the feedpoint impedance and has no effect whatever on the antenna's radiation. Nobody has ever said it affected the antenna's radiation so that has been and is still just a straw man. As the inductor gets longer, it does become some part of the antenna, but adding an inductor which resonates, say, a 45 degree physical radiator doesn't make the antenna act like a 90 degree physical radiator. Of course not and nobody has ever said it does. It increases the electrical length and brings the forward and reflected waves into phase with each other. That's why the the feedpoint impedance is resistive. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Ian White GM3SEK wrote:
The disagreement is entirely about the interpretation - in other words, it's about the theory about standing and travelling waves. Richard habitually misses out this step, which makes it look as if the Bird wattmeter "proves" the physical existence of forward and reverse travelling waves of power. Those are traveling waves of *EM energy* where the power is indicated at a point as the energy flows through that point. Assuming Z0=50 ohms, the Bird indicates the number of joules per second flowing toward the load when the slug is in the forward position. Turning the slug around causes the Bird to indicate the number of joules per second flowing toward the source. The only way to have standing waves of EM energy in a transmission line is to have two EM waves flowing in opposite directions. I have asked you before to explain how standing waves develop without the existence of a forward traveling wave and a rearward traveling wave. Your silence on that subject has been conspicuous by its absence. Do standing waves appear by magic? It doesn't. Everything that you see printed on the Bird's meter scale, and in the Bird literature, represents that company's particular interpretation of theory about waves on transmission lines. The details of that theory are *not* agreed within this newsgroup, which means that - to some people - the two halves of Richard's claim do not join up. Are you asserting that Bird is engaging in false advertising? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Ian White GM3SEK wrote:
[SNIP] The disagreement is entirely about the interpretation - in other words, it's about the theory about standing and travelling waves. Richard habitually misses out this step, which makes it look as if the Bird wattmeter "proves" the physical existence of forward and reverse travelling waves of power. It doesn't. Everything that you see printed on the Bird's meter scale, and in the Bird literature, represents that company's particular interpretation of theory about waves on transmission lines. The details of that theory are *not* agreed within this newsgroup, which means that - to some people - the two halves of Richard's claim do not join up. Ian, I've not detected this particular disagreement about waves on transmission lines in the group. I would be most grateful to see a brief statement of where and how Bird's interpretation of theory is found infirm. 73, Chuck NT3G |
Current across the antenna loading coil - from scratch
wrote:
The loading coil doesn't "replace" missing electrical degrees, it primarily corrects power factor by compensating reactance. If correcting the power factor didn't cause a phase shift, the power factor wouldn't change but we know it does. That phase shift is exactly what we are talking about. The coil shifts the phase of both the forward wave and reflected wave thus furnishing some much needed electrical degrees in order to resonate the antenna by bringing the phasor sum of the forward and reflected voltages into phase with the phasor sum of the forward and reflected currents. Any power engineering textbook will tell you what happens to the phase when the power factor is corrected. Hint: If the phase stayed the same, as you assert, nothing would change. But we know that correcting the power factor changes the phase. That's exactly what correcting the power factor is all about. The truth is the loading inductor almost never has the same phase shift in current as the missing antenna area it replaces, and it almost never has the same "current drop". The inductor does indeed contribute a phase shift that is not zero. In a one wavelength system, the coil can just as easily contribute a current RISE as a current DROP. That fact alone is reason to drop the flawed model. Current cannot be created in a coil by sucking it out of earth ground which is what your theory have us believe. But of course, you have refused to discuss the subject. I can have an antenna of given dimensions with a loading coil at one fixed spot. The difference in current flowing into one end and out the other can go all over the place, depending only on the coil's physical design wity the antenna resonant on the same frequency. This happens ONLY by changing the coil. Of course, but that is beside the point. Every real world inductor does contribute its own unique phase shift and its own unique current change, rise, fall, or equal at current nodes and antinodes. You have absolutely refused to discuss that current rise. One wonders why. If I had a coil that was compact and not against the groundplane with low stray capacitance compared to the antenna area above the coil, current difference between each terminal or through the coil could be immeasurable with reasonably good instrumentation. Phase shift in current could also be nearly zero. None of this would be anywhere near the area the coil replaces. Resorting to a specially designed coil completely different from anything used in the real world has been your specialty. If your theory only works for only one special case and is not valid for the general case, it's time to junk that theory. After failing a dozen times to achieve equal current at both ends of numerous coils, you finally declared victory using a small toroidal coil. Uhhhh Tom, one out of twelve doesn't prove much. I have shown you how to achieve equal current with any coil. It just depends upon where the coil is placed in the standing wave environment. A few people have violated the rules of charge conservation, charge movement, and misapplied the concept of standing waves, but the single largest error is standing behind the myth or misconception that that loading coil somehow acts like the "missing area of antenna". The coil's function is to bring the forward and reflected waves into phase so the feedpoint impedance will be purely resistive. It cannot do that if it has no effect on phase. Your theory is full of holes. The coil affects the electrical length of the antenna, not the physical length. Nobody has ever said it replaces the missing physical length of the antenna. Your implication is that same tired old straw man riding that same old dead horse. Please stop trying to twist what we are saying and fix the twist in your own misconceptions. For instance, how does your theory handle a current rise through a coil as illustrated at: http://www.qsl.net/w5dxp/test316.GIF in the right hand part of the graphic. Why do you refuse to discuss this current RISE? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
K7ITM wrote:
In your two messages included above by reference, you complained that I had in the other two included messages put things you had written, but that I did not properly attribute them to you. I don't know whether to be offended, feel sorry for you, or laugh. In each of my two messages, immediately following my signature, is a line that begins, "Cecil wrote..." I trust it's not too difficult for most folk to understand, but I'll explain it for you. That line means that YOU wrote the stuff that follows that line, not me. In general, I would absolutely NOT want anyone to think I'd written anything you wrote! Guess I'm inclined to feel a bit of the second, and do some of the third. You are doing the "Cecil wrote" in the wrong way and falsifying attributions in the process. If you want to be known as the netnews guy who falsifies attributions, that is your business. What I am officially asking you to do is to cease and desist falsifying the attributions associated with my postings. -- 73, Cecil http://www.qsl.net/w5dxp |
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