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#131
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On Sep 17, 6:11*pm, joe wrote:
Art Unwin wrote: snip In direct terms I have stated that current flows down the center of a radiator if it is of a fractional wave length. OK, you must be talking about an AC current as there is a wavelength involved. But if you are implying there is current in the center matching the amplitude of the current on the surface you are wrong. See this linkhttp://en.wikipedia.org/wiki/Skin_depth Note the phrase regarding current;"the magnitude of which is greatest at the conductor's surface". This is where the current is. There is also this statement "the current can be flowing in the opposite direction to that at the surface." Note that there are qualifications on that statement (on the page referenced). So, while there can be some current flowing inside the conductor, it does not say it is a matching current in the other direction. By saying most of the current is at the surface, it conflicts with your statement. A very simple statement which nobody wishes to address. You are trying to apply "For a force there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions." (from "http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion" ) You make a simple statement, brought about but applying a concept incorrectly. I don't think Newton said anything about electricity and flow in conductors. Newton's law doesn't say what the opposing force is, so I don't think you can say it is anything specific. snip I would prefer however the discussion to at least start with equilibrium which leads to why or why not it is correct that current can flow thru the center of a conductor the answer of which is not in the books. The right books would tell you that AC current does not flow in the center of a conductor. As others have stated, you need to clearly define what _you_ mean by equilibrium. Some people prefer to read the last page of the book first. I prefere to examine foundations before determining the merits of a house. Those foundations need to take into account all the considerations, not just the ones you know or want to talk about. You may have read some of the book, but you skipped quite a few chapters. Regards Art Consider your statement to have been addressed. You will note that both links include some math. This is something you don't provide with your explanations. If you went through the rigor to work out the math and present it to the group with sufficient clarity you might get someone to believe you. If you want someone to believe you, it is up to you to effectively communicate your ideas. It is hard to tell if you have a useful concept regarding antennas, are completely lost, or just a troll. But, just in case you have something, then... Many antennas are built using tubing for light weight. So, if there is a current flowing in the middle, it is good that the ends of the tubes are crimped, or plugged. I wouldn't want the flowing electrons spilling out onto my lawn. I know books say a lot of things but do they explain WHY current cannot flow thru the center? Somebody said the current flow backwards now that is hard to understand unles he is refering to a tank circuit where the antenna has capacitance at one end and inductance at the other and the current goes nowhere. I think I will sit back and see what the experts say and if the IEEE has accepted al these explanations. One thing I particularly have difficulty with is that the secondary current can overcome the primary current where the power flows back to a wall plug or something like that. Another infers that current travel in a aluminum tube is different to the flow of a solid conductor presumably with double the surface area you have double the amount of radiation. The next publication from the ARRL is going to rock the science world with these findings on radiation. Funny thing is that based on my findings I designed an antenna which computer program AO Pro determined was quite good, an arrangement that is if the program doesn;'t follow the teachings of the books should I then throw the program away? NEC4 models the antenna that is in equilibrium also isn't that a bummer? If only somebody would come up with a vector diagram of a radiator that was NOT in equilibrium I could locate my fault very quickly. Still if all of what has been described will be published in the ARRL and IEEE papers I can afford to wait. Thank you all Art |
#132
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Cecil Moore wrote:
John Smith wrote: Where is motion? Velocity = c Where is time? Time stands still for anything traveling at velocity = c Yeah, well, if you take a cubic centimeter of "energy" around yourself, of even myself, for that matter, it better be at rest! Otherwise, the motion/time thing, which your simplistic equation ignores, will, MOST CERTAINLY, come into play ... However, the equation you gave is good ... but just NOT that simple for REAL world situations ... but then, I stated that, before you gave the equation ... You have argued this yourself, most vehemently, with photons ... think about it ... an argument I actually agreed with, and echo here ... motion DOES change things, a bit ... and, it is VERY DIFFICULT to keey energized particles at rest, but then, not impossible ;-) Regards, JS |
#133
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On Sep 17, 5:16*pm, "Frank" wrote:
In direct terms I have stated that current flows down the center of a radiator if it is of a fractional wave length. A very simple statement which nobody wishes to address. Fine by me, the thread would then have a single posting and the multitude can generate questions and discussion about deep space or other topics of choice. Severns, QEX, Nov/Dec 2000, pp 20-29 does address the issue. On page 22: "At some points within the wire, the instantaneous current is actually flowing backwards (minus signs) due to the self-induced eddy currents that are the underlying phenomena responsible for skin effect." These results were verified with Ansoft's "Maxwell" FEM software. An excellent treatment of the math can be found at:http://www.g3ynh.info/zdocs/comps/zint.html Frank I read that last one Frank but I think it is aimed at computer geeks which I am not. Pleased to see eddy currents are the underlying phenomina responsible for skin depth presumably he explains how the secondary current can overcome that which creats it. At last we have a source for free energy Regards Art |
#134
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#135
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On Sep 17, 5:52*pm, Cecil Moore wrote:
wrote: Are you proposing that a photon cannot travel slower than the speed of light in a vacuum, or it cannot travel slower than the speed of light in water or the speed of light through glass or air? In any random medium, a photon cannot travel slower than the speed of light through that medium. In particular, photons associated with standing waves do NOT stand still. -- 73, Cecil *http://www.w5dxp.com What about Cerenkov radiation? In this case, beta particles with mass travel faster than light in a water medium. So much for 'nothing can travel faster than a photon'. It depends on the medium. If the medium is a vacuum, then yes, nothing can travel faster than the speed of light in that medium. Need to be careful. I have to Credit R. Clark for pointinmg this out some time ago. See http://nuclear.mst.edu/research/reactor.html |
#136
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Rectifier wrote:
The first nine words in my first statement above are not mine but were copied verbatim from Rectifier's posting (except for the misspelled word). If there was an implication that light can travel at less than the speed of light, it didn't come from me. -- 73, Cecil http://www.w5dxp.com Light travels at different speeds in different media, such as water, glass, etc. And yet all are the speed of light. In that media. What's your issue with that? tom K0TAR |
#137
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I read that last one Frank but I think it is aimed at computer geeks
which I am not. Pleased to see eddy currents are the underlying phenomina responsible for skin depth presumably he explains how the secondary current can overcome that which creats it. At last we have a source for free energy Regards Art Not sure if you got the correct site Art, since there should be nothing concerning computers at: http://www.g3ynh.info/zdocs/comps/zint.html. Also the excellent references at: http://www.g3ynh.info/zdocs/comps/refs.html Note that the central current in the conductor is significantly less than than the surface current. Solution of the Kelvin functions should be easy with Mathcad, or similar, providing only the first few terms of the series are considered. Direct computation of these modified Bessel functions is limited to the latest versions of Mathcad, since the earlier versions cannot handle complex arguments. A more rigorous treatment can be found at the following: http://mathworld.wolfram.com/KelvinFunctions.html http://mathworld.wolfram.com/Bei.html http://mathworld.wolfram.com/Ber.html Where, even with Mathcad 7, using the 20, or so, first terms of the series expansions, I have gotten good agreement with the published curves. Mathcad certainly does not like the upper limits of the series to be infinity. Probably even Excel could handle it. 73, Frank |
#138
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Art Unwin wrote:
I know books say a lot of things but do they explain WHY current cannot flow thru the center? snip Art If you do the differential equations, it doesn't say why the center can't so much as why the skin does. Similar to gravitation and water flowing downhill vs uphill. I'll go into detail if you can't figure it out. Or not. tom K0TAR |
#140
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On Sep 17, 8:52*pm, Tom Ring wrote:
Art Unwin wrote: I know books say a lot of things but do they explain WHY current cannot flow thru the center? snip Art If you do the differential equations, it doesn't say why the center can't so much as why the skin does. *Similar to gravitation and water flowing downhill vs uphill. *I'll go into detail if you can't figure it out. *Or not. tom K0TAR Please do. I would love to see your take on it. I am gratified that somebody is tackling the problem hopefully in laymans language so all can benefit. Possibly you could start another thread as this one is greatly contaminated I can then respond on my take of the matter and hopefully the flaw will be exposed. Regards Art |
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