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#21
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On Sat, 12 Sep 2009 12:45:28 +0100, "christofire"
wrote: Well the title of the thread is 'Spherical radiation pattern' and I interpret that as meaning a far-field pattern that is uniform (within the 2 dB margin I offered) in respect of the transverse electric, or transverse magnetic, field strength, or the resulting power-flux density, over a whole sphere. Hi Chris, Well, simply put this antenna with its mirror image elements into free space and it accomplishes that quite easily. What is the red line in the pattern to which you gave the link? XYZ Axis. 73's Richard Clark, KB7QHC |
#22
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On Sat, 12 Sep 2009 08:23:17 -0700 (PDT), Art Unwin
wrote: Google... small efficient antenna steven best http://www.cst.com/Content/Applications/Article/A+Small,+Efficient,+Linear-polarized+Omni-directional+Antenna The antenna fits inside a sphere of radius 0.0415 wavelengths. However, the antenna pattern is not spherical and more closely resembles the torus produced by a dipole than of an isotropic antenna. http://www.cst.com/CMS/images/article105/CPU05_047_600_481.jpg An isotropic approximation, which doesn't really qualify for the prize because the pattern is not polarization and phase insensitive. http://802.11junk.com/jeffl/antennas/isotropic/index.html -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#23
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![]() "Richard Clark" wrote in message ... On Sat, 12 Sep 2009 12:45:28 +0100, "christofire" wrote: Well the title of the thread is 'Spherical radiation pattern' and I interpret that as meaning a far-field pattern that is uniform (within the 2 dB margin I offered) in respect of the transverse electric, or transverse magnetic, field strength, or the resulting power-flux density, over a whole sphere. Hi Chris, Well, simply put this antenna with its mirror image elements into free space and it accomplishes that quite easily. Have you ever built one and measured its radiation pattern? Chris |
#24
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On Sat, 12 Sep 2009 17:50:52 +0100, "christofire"
wrote: Have you ever built one and measured its radiation pattern? Hi Chris, Others have - the design is not unique to me and has been around for years. I modeled it to merely confirm those reports and that was rather simply accomplished. I have reported these results to interested parties here for the last 10 to 15 years. I am under no illusion that Art has ever used that data as a resource, otherwise it would undercut his claim of novelty. I've no doubt that other designs meeting your terse requirements could be rummaged up. I have no presumption that NEC fails for this one specific design that is ordinary in every regard to conventional modeling. At a minimum this is only 4 wires. As such, I am satisfied. 73's Richard Clark, KB7QHC |
#25
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![]() "Richard Clark" wrote in message ... On Sat, 12 Sep 2009 17:50:52 +0100, "christofire" wrote: Have you ever built one and measured its radiation pattern? Hi Chris, Others have - the design is not unique to me and has been around for years. I modeled it to merely confirm those reports and that was rather simply accomplished. I have reported these results to interested parties here for the last 10 to 15 years. I am under no illusion that Art has ever used that data as a resource, otherwise it would undercut his claim of novelty. I've no doubt that other designs meeting your terse requirements could be rummaged up. I have no presumption that NEC fails for this one specific design that is ordinary in every regard to conventional modeling. At a minimum this is only 4 wires. As such, I am satisfied. 73's Richard Clark, KB7QHC Good. Maybe this will encourage Art to have a go at my challenge by applying his own theories then. I had seen papers about inverted F antennas before (at an IEE or IET symposium some ten years ago), and I vaguely recall hearing that some manufacturers use them in mobile phones, but I'd never seen a pattern as uniform as the result of your simulation. Chris |
#26
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![]() "christofire" wrote in message news ![]() "Richard Clark" wrote in message ... On Sat, 12 Sep 2009 17:50:52 +0100, "christofire" wrote: Have you ever built one and measured its radiation pattern? Hi Chris, Others have - the design is not unique to me and has been around for years. I modeled it to merely confirm those reports and that was rather simply accomplished. I have reported these results to interested parties here for the last 10 to 15 years. I am under no illusion that Art has ever used that data as a resource, otherwise it would undercut his claim of novelty. I've no doubt that other designs meeting your terse requirements could be rummaged up. I have no presumption that NEC fails for this one specific design that is ordinary in every regard to conventional modeling. At a minimum this is only 4 wires. As such, I am satisfied. 73's Richard Clark, KB7QHC Good. Maybe this will encourage Art to have a go at my challenge by applying his own theories then. I had seen papers about inverted F antennas before (at an IEE or IET symposium some ten years ago), and I vaguely recall hearing that some manufacturers use them in mobile phones, but I'd never seen a pattern as uniform as the result of your simulation. Chris art will never accept your challenge. its up to you to prove that his assertions are incorrect... and then get ignored as he continues to state the same things in many different forms. unless you can capture one of his diamagnetic levitating solar neutrinos and show that it doesn't sit on the antenna element and jump off when a pulse of current hits it you will never be believed... and even if you did capture one he would tell you it changed in flight from the sun. |
#27
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On Sat, 12 Sep 2009 19:25:16 +0100, "christofire"
wrote: I had seen papers about inverted F antennas before (at an IEE or IET symposium some ten years ago), and I vaguely recall hearing that some manufacturers use them in mobile phones, but I'd never seen a pattern as uniform as the result of your simulation. Hi Chris, For a more academic treatment, the antenna is also known as the "U-Shaped Antenna of Shtrikman." His has three wires, my fourth wire is much like the J-Pole feed point attachment. Now, one proviso: this is not an isotropic in the sense of providing equal polarization at any angle. Nothing can accomplish that due to that requirement being impossible to meet (the so-called "hairy ball" problem). So, I simply resolved that with my carbon golf ball with its thermistor for detecting the Inverted F's total field to within the degree of less than 2dB variation over the shell surrounding the antenna. Good. Maybe this will encourage Art to have a go at my challenge by applying his own theories then. As I've shown, they are not his theories. Art doesn't have theories, they are illusions. Shtrikman's antenna has a model and a practical, real example that agree with one another in performance. The design is revealed and can be reproduced by anyone. No advanced math is demanded to perfect the results. No allusion to nuclear forces is required to explain any principle. Anyone can, and HAS built an antenna that Art can only mumble about. Perhaps I am mislead about this mumble, having kill-filed him, as I see his contribution (sic) only through other's quotes; few of which are full quotes (I can understand why). This last week in my driving through rain city, I've seen a street corner beggar who has worked one particular intersection for a couple of years now. He has a weather protected laminated board describing his plea, and he wears goretex weather gear that I couldn't afford. He does have this hang-dog appearance and shambling shuffle tho'. What is one to believe when it comes to claims? Clearly money talks. Who knows? He may have a patented system and sells franchises. 73's Richard Clark, KB7QHC |
#28
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![]() "Richard Clark" wrote in message ... On Sat, 12 Sep 2009 19:25:16 +0100, "christofire" wrote: I had seen papers about inverted F antennas before (at an IEE or IET symposium some ten years ago), and I vaguely recall hearing that some manufacturers use them in mobile phones, but I'd never seen a pattern as uniform as the result of your simulation. Hi Chris, For a more academic treatment, the antenna is also known as the "U-Shaped Antenna of Shtrikman." His has three wires, my fourth wire is much like the J-Pole feed point attachment. Now, one proviso: this is not an isotropic in the sense of providing equal polarization at any angle. Nothing can accomplish that due to that requirement being impossible to meet (the so-called "hairy ball" problem). I had understood it to be impossible on the basis of normal physics but Art Unwin's claim wasn't clear in respect of polarisation. So, I simply resolved that with my carbon golf ball with its thermistor for detecting the Inverted F's total field to within the degree of less than 2dB variation over the shell surrounding the antenna. Now I understand what you meant by 'total field' - sum of powers of components in all polarisations. Good. Maybe this will encourage Art to have a go at my challenge by applying his own theories then. As I've shown, they are not his theories. Art doesn't have theories, they are illusions. Shtrikman's antenna has a model and a practical, real example that agree with one another in performance. The design is revealed and can be reproduced by anyone. No advanced math is demanded to perfect the results. No allusion to nuclear forces is required to explain any principle. Anyone can, and HAS built an antenna that Art can only mumble about. Perhaps I am mislead about this mumble, having kill-filed him, as I see his contribution (sic) only through other's quotes; few of which are full quotes (I can understand why). Shtrikman's antenna sounds interesting. I will look up references. This last week in my driving through rain city, I've seen a street corner beggar who has worked one particular intersection for a couple of years now. He has a weather protected laminated board describing his plea, and he wears goretex weather gear that I couldn't afford. He does have this hang-dog appearance and shambling shuffle tho'. What is one to believe when it comes to claims? Clearly money talks. Who knows? He may have a patented system and sells franchises. 73's Richard Clark, KB7QHC Over here we've recently been subjected to the phenomenon of 'Seasick Steve' - who 'started out with nothing and still has most of it left' but also has a substantial recording contract. What is one to believe, as you so rightly say? Chris |
#29
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On Sun, 13 Sep 2009 02:08:20 +0100, "christofire"
wrote: I had understood it to be impossible on the basis of normal physics but Art Unwin's claim wasn't clear in respect of polarisation. Hi Chris, Black body radiators do qualify as Isotropic; and as Art has claimed high efficiencies for RF impracticalities, it must be for efficient Infrared emission. 73's Richard Clark, KB7QHC |
#30
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![]() "christofire" wrote ... Now I understand what you meant by 'total field' - sum of powers of components in all polarisations. Does one wave has many polarizations, or one antenna has many polarizations? Which one: transmitter or receiver? Could you teach me? A* |
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