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#11
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![]() "Art Unwin" wrote in message ... On Nov 6, 9:10 pm, tom wrote: Art Unwin wrote: On Nov 5, 10:11 pm, tom wrote: Art Unwin wrote: What is the best antenna for use with all circular, horizontal, vertical and other polarizations without drastic fall of in gain, and without changes in angular position and feed point via switches e.t.c at the tower top? Maybe the quadrifilar helix. tom K0TAR That is made for a single circulation signal only. Then it's a point driven against ground that you need. Or a 2 point dipole. Either one with a lossless transmission line would work. That's the only thing that will do all you want and do both RHC and LHC polarizations and do it at all frequencies. I have to assume you want all frequencies since you haven't responded on that question. And it will have a very unusable impedance at all frequencies. But if you can do the lossless line, you are probably covered on the lossless tuner, too. Good luck. You want everything, and you can't have it. And "single circulation" is not the proper terminology (as usual), although I am somewhat sure about what you meant. tom K0TAR I wanted to know if there was such a radiator in the system that could do such a thing and apparently there is not! I am working on one that will do it but I wanted to be sure if I was not reinventing the wheel. My antenna is based on using something like a ladder line only with the wires closer together to provide a lower impedance. If you close both ends of such a line and wind a helix with it you can get a radiator beam that will do all the things I suggested except the "all frequency" part which requires further additions . If you have two open wires in parallel and slide a cross connector up and down the two wires the resonant frequency changes dependent on the length where the jumper is. Thus, if you literally make the ladder line into a true ladder by fixing a lot of conductive cross rungs on the ladder, the applied current will cross over at the point that the circuit is resonant. This way the radiator will get the "all frequency" attributes. Such a radiator becomes a much physically smaller radiator than is being used today. Why not try it.?... It is the proverbial free lunch! Are you saying a wave on a transmission line will continue to propagate beyond a short-circuit across the line? If so, you've missed something important. Chris |
#12
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On Nov 7, 10:48*am, "christofire" wrote:
"Art Unwin" wrote in message ... On Nov 6, 9:10 pm, tom wrote: Art Unwin wrote: On Nov 5, 10:11 pm, tom wrote: Art Unwin wrote: What is the best antenna for use with all circular, horizontal, vertical and other polarizations without drastic fall of in gain, and without changes in angular position and feed point via switches e.t..c at the tower top? Maybe the quadrifilar helix. tom K0TAR That is made for a single circulation signal only. Then it's a point driven against ground that you need. Or a 2 point dipole. Either one with a lossless transmission line would work. That's the only thing that will do all you want and do both RHC and LHC polarizations and do it at all frequencies. I have to assume you want all frequencies since you haven't responded on that question. And it will have a very unusable impedance at all frequencies. But if you can do the lossless line, you are probably covered on the lossless tuner, too. Good luck. You want everything, and you can't have it. And "single circulation" is not the proper terminology (as usual), although I am somewhat sure about what you meant. tom K0TAR I wanted to know if there was such a radiator in the system that could do such a thing and apparently there is not! I am working on one that will do it but I wanted to be sure if I was not reinventing the wheel. My antenna is based on using something like a ladder line only with the wires closer together to provide a lower impedance. If you close both ends of such a line and wind a helix with it you can get a radiator beam that will do all the things I suggested except the "all frequency" part which requires further additions . If you have two open wires in parallel and slide a cross connector up and down the two wires the resonant frequency changes dependent on the length where the jumper is. Thus, if you literally make the ladder line into a true ladder by fixing a lot of conductive cross rungs on the ladder, the applied current will cross over at the point that the circuit is resonant. This way the radiator will get the "all frequency" attributes. Such a radiator becomes a much physically smaller radiator than is being used today. Why not try it.?... It is the proverbial free lunch! Are you saying a wave on a transmission line will continue to propagate beyond a short-circuit across the line? *If so, you've missed something important. Chris Not sure what you are getting at Chris. The applied current will travel the 1/2 WL of the radiator/ transmission line and then turn so it will be at resonant impedance at the input, at the impedance value of the line. The current will not continue to travel any further than when the closed circuit that is resonant is reached. In other words, a transmission line can be seen as having the same impedance or load at each end at a given frequency. If you close one end, is it not still resonant? If you want to dig further look at my home page unwinantennas to see where I am coming from. This is the same principle used when matching a radiator with transmission line sections as shown on a nearby current thread ( at least that is the way I see it but then I could still be a fraud by any other name!) I have done this many times in practice BUT it may well be the "why's) that I am misinterpreting. On the other hand I cannot see how a AC circuit wil short across as you have intimated. Again I could be wrong as usual! When I model such an arrangement it provides gain in the order of 10dbi +/- 1.5 db regardless of the type of radiation that is directed at it. Well one type doesn't work out well but I don't know where it is usedn in today's world |
#13
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On Sat, 7 Nov 2009 16:48:55 -0000, "christofire"
wrote: My antenna is based on using something like a ladder line only with the wires closer together to provide a lower impedance. .... Thus, if you literally make the ladder line into a true ladder by fixing a lot of conductive cross rungs on the ladder, the applied current will cross over at the point that the circuit is resonant. Hi Chris, So, you want to turn a massively shorted thin transmission line into a radiator? How does the current get past the first short? It cannot, so that string of shorts up the line are redundant and you can remove them. This leaves you with a very small loop very close to the transmitter. Almost every ham has tried working into a short and has never found it productive. Have you tried it? 73's Richard Clark, KB7QHC |
#14
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On Thu, 5 Nov 2009 17:50:18 -0800 (PST), Art Unwin
wrote: What is the best antenna for use with all circular, horizontal, vertical and other polarizations without drastic fall of in gain, and without changes in angular position and feed point via switches e.t.c at the tower top? A light bulb might work. It will pickup (or radiate) any polarization type and direction. An unshielded dummy load might also work. It won't have much gain, but it will meet your criteria for bandwidth and polarization. It's also kinda cool looking. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#15
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On Fri, 6 Nov 2009 08:05:17 -0800 (PST), Art Unwin
wrote: On Nov 5, 10:11*pm, tom wrote: Art Unwin wrote: What is the best antenna for use with all circular, horizontal, vertical and other polarizations without drastic fall of in gain, and without changes in angular position and feed point via switches e.t.c at the tower top? Maybe the quadrifilar helix. tom K0TAR That is made for a single circulation signal only. It might be done with 4 quadrifilar antennas. Each antenna has a hemispherical pattern and one sense (left or right hand). With 4 antennas and a suitable combiner, each antenna will cover one half of the pattern, and one of the two available senses. The quadrifilar antenna will work with linear polarization, but at reduced gain. The usable bandwidth is probably insufficient to cover DC to light, but multiple quadrifilar antennas can be attached to the surface of a ball, resulting in a sperical pattern approximation and a construction that looks like a puffer fish. It's also possible to conglomerate the quadrifiler into a tapered helix, thus increasing the bandwidth at the expense of gain. For VLF, shove a ferrite rod into the middle. You can also do random polarizations by using leaky coax, tangled into a Gordian Knot. Some part of the knot will undoubtably be parallel to the random polarization, and thus provide some signal pickup. Gain will be limited by the length of the lossy coax and size of the knot. http://www.afltele.com/products/fiber_optic_cable/coax_cable/leaky_coax/ http://en.wikipedia.org/wiki/Gordian_knot Marginally related drivel: http://www.wifi-plus.com http://www.connectronics.com/wifi_plus/ "The world's first MULTI-POLARIZED - MULTI-PATH Antenna with GEO-Spatial capture". -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#16
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On Sat, 07 Nov 2009 10:32:56 -0800, Jeff Liebermann
wrote: tangled into a Gordian Knot. oooooooooooooh, I like that one. I bet Einstein (that ol' refrigerator mechanic) never anticipated that when he was trying to juggle leptons. What could he have been thinking? 73's Richard Clark, KB7QHC |
#17
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![]() "Richard Clark" wrote in message ... On Sat, 7 Nov 2009 16:48:55 -0000, "christofire" wrote: My antenna is based on using something like a ladder line only with the wires closer together to provide a lower impedance. ... Thus, if you literally make the ladder line into a true ladder by fixing a lot of conductive cross rungs on the ladder, the applied current will cross over at the point that the circuit is resonant. Hi Chris, So, you want to turn a massively shorted thin transmission line into a radiator? How does the current get past the first short? It cannot, so that string of shorts up the line are redundant and you can remove them. This leaves you with a very small loop very close to the transmitter. Almost every ham has tried working into a short and has never found it productive. Have you tried it? 73's Richard Clark, KB7QHC Shouldn't you be addressing Art Unwin with that? ... it's he who's proposing the idea, not me. Perhaps the behaviour of Outlook Express has led to confusion (again?), despite my leaving a double line space between the OP and my comment. Chris |
#18
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On Sun, 8 Nov 2009 00:49:07 -0000, "christofire"
wrote: "Richard Clark" wrote in message .. . On Sat, 7 Nov 2009 16:48:55 -0000, "christofire" wrote: My antenna is based on using something like a ladder line only with the wires closer together to provide a lower impedance. ... Thus, if you literally make the ladder line into a true ladder by fixing a lot of conductive cross rungs on the ladder, the applied current will cross over at the point that the circuit is resonant. Hi Chris, So, you want to turn a massively shorted thin transmission line into a radiator? How does the current get past the first short? It cannot, so that string of shorts up the line are redundant and you can remove them. This leaves you with a very small loop very close to the transmitter. Almost every ham has tried working into a short and has never found it productive. Have you tried it? 73's Richard Clark, KB7QHC Shouldn't you be addressing Art Unwin with that? ... it's he who's proposing the idea, not me. I've consigned Art's evacuations to the trashbin. Perhaps the behaviour of Outlook Express has led to confusion (again?), despite my leaving a double line space between the OP and my comment. Chris Hi Chris, I don't know about a double line being a convention for that, but as you can see above, this time quoting is proceeding as natural. So, this shorted transmission line is Art's? Has he ever, ever reported a QSO outside of his zip code? 73's Richard Clark, KB7QHC |
#19
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![]() "Helmut Wabnig" hwabnig@ .- --- -. dotat wrote ... On Fri, 6 Nov 2009 05:40:21 -0800 (PST), Art Unwin wrote: On Nov 6, 4:23 am, Helmut Wabnig hwabnig@ .- --- -. dotat wrote: On Thu, 5 Nov 2009 17:50:18 -0800 (PST), Art Unwin wrote: What is the best antenna for use with all circular, horizontal, vertical and other polarizations without drastic fall of in gain, and without changes in angular position and feed point via switches e.t.c at the tower top? Frequency range? w. 10 thru 160 metres amateur bands! OK, here is my answer: A SHORT PIECE OF WIRE. Thin or thick? S* |
#20
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![]() Uzytkownik "Jeff Liebermann" napisal w wiadomosci ... On Thu, 5 Nov 2009 17:50:18 -0800 (PST), Art Unwin wrote: What is the best antenna for use with all circular, horizontal, vertical and other polarizations without drastic fall of in gain, and without changes in angular position and feed point via switches e.t.c at the tower top? A light bulb might work. It will pickup (or radiate) any polarization type and direction. An unshielded dummy load might also work. It won't have much gain, but it will meet your criteria for bandwidth and polarization. It's also kinda cool looking. "An unshielded dummy load might also work". So the cool looking ladder also. S* |
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