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Art wrote,
Tom, I wouldn't be so quick in using the term " impossible" if I were you until the facts come out. He has already stated that he has a distributed load antenna which he referres to as a two dimensional helix, which I see as a meander line on a circuit board. This ofcourse, provides an antenna of very small size which has some drawbacks. But the inventor states that the design is a combination of known ideas which may well be a method of overcomming initial drawbacks. After all a University have placed themselves behind the inventor and most of us did not go to University on a platform of disbelieving our professors . Even if it all turns out to be a mistaken idea the majority of hams will learn from future interchange rather than tagging along with those who believe all is already known.Usually the best inventions are an amaqlgamation of all the good observations noted in otherwise bad ideas/inventions made by somebody who looks for every morsel that is new and is resourceful enough to connect the dots before it becomes obvious to the followers.It is rare that someting that comes along is totally new in its entirety. Regards Art Hi Art, he may very well have produced an antenna that works as advertised. Time will tell. However, in evaluating the claims of anyone who invents something new it is always advisable to compare those claims with current theory before accepting them wholeheartedly. It isn't impossible to make a small, useful, antenna - the small-in-terms-of-wavelength loop is a case in point - but to make a small antenna with all the characteristics of a large antenna strains the credibility. It sounds as if this gentleman is trying to take advantage of the properties of the double-tuned circuit in order to achieve a larger bandwidth while maintaining good efficiency. If so, it's an interesting idea and I hope it works, but I'm not going to get excited about it until I know more, such as, what happens to the radiation pattern when the current in the top part of the antenna is out of phase with the current in the bottom part? Does it then radiate straight up, or does he have some method of controlling the phase so it doesn't do this? 73, Tom Donaly, KA6RUH |
Art Unwin KB9MZ wrote:
Tom, I wouldn't be so quick in using the term " impossible" if I were you until the facts come out. He has already stated that he has a distributed load antenna which he referres to as a two dimensional helix, which I see as a meander line on a circuit board. This ofcourse, provides an antenna of very small size which has some drawbacks. But the inventor states that the design is a combination of known ideas which may well be a method of overcomming initial drawbacks. After all a University have placed themselves behind the inventor and most of us did not go to University on a platform of disbelieving our professors . Even if it all turns out to be a mistaken idea the majority of hams will learn from future interchange rather than tagging along with those who believe all is already known.Usually the best inventions are an amaqlgamation of all the good observations noted in otherwise bad ideas/inventions made by somebody who looks for every morsel that is new and is resourceful enough to connect the dots before it becomes obvious to the followers.It is rare that someting that comes along is totally new in its entirety. Regards Art (Tdonaly) wrote in message ... Mike wrote, What I have become stuck on is the claim of constant current along the length of the antenna - or 80 percent as claimed. How does this work? I don't profess to know much about these matters, but if the current stays the same, then the voltage must too? And i still can't figure out how such an efficient antenna "melts". 8^) - Mike KB3EIA - Anyone can make a "constant current" dipole, just by making it small enough in relation to the wavelength of the frequency it's to be used for. Of course, as has been pointed out here many times, feeding such an antenna would be difficult to impossible, and bandwidth would be small, but you can't have everything. Well, I suppose that I could have qualified that as an antenna that works! 8^) Some theorists in the late 1940's did some work on the fundamental limits of small antennas. There are one or two papers available on the web if you search for "small antennas" with google. People who think they can make a small (in terms of a wavelength) single radiator antenna, with good efficiency, and a large bandwidth, that doesn't have to resort to feedline radiation to achieve its aims, would do well to read these papers before making themselves look silly by claiming the impossible. It would seem that way to me. From the description, I got the visualization of a hollow tube, with perhaps three main parts. A center conductor, which would be the helix. outside of this would be a vertical wire running from top to bottom. I would assume these to be ground wire, and serve as half of the capacitor function. There might be some version of little hats attached to the helix from top to bottom as the other part of the capacitor(s). Will it work? "work" is so subjective..... - Mike KB3EIA - |
Art Unwin KB9MZ wrote:
Tom, I wouldn't be so quick in using the term " impossible" if I were you until the facts come out. He has already stated that he has a distributed load antenna which he referres to as a two dimensional helix, which I see as a meander line on a circuit board. This ofcourse, provides an antenna of very small size which has some drawbacks. But the inventor states that the design is a combination of known ideas which may well be a method of overcomming initial drawbacks. After all a University have placed themselves behind the inventor and most of us did not go to University on a platform of disbelieving our professors . Even if it all turns out to be a mistaken idea the majority of hams will learn from future interchange rather than tagging along with those who believe all is already known.Usually the best inventions are an amaqlgamation of all the good observations noted in otherwise bad ideas/inventions made by somebody who looks for every morsel that is new and is resourceful enough to connect the dots before it becomes obvious to the followers.It is rare that someting that comes along is totally new in its entirety. Regards Art (Tdonaly) wrote in message ... Mike wrote, What I have become stuck on is the claim of constant current along the length of the antenna - or 80 percent as claimed. How does this work? I don't profess to know much about these matters, but if the current stays the same, then the voltage must too? And i still can't figure out how such an efficient antenna "melts". 8^) - Mike KB3EIA - Anyone can make a "constant current" dipole, just by making it small enough in relation to the wavelength of the frequency it's to be used for. Of course, as has been pointed out here many times, feeding such an antenna would be difficult to impossible, and bandwidth would be small, but you can't have everything. Well, I suppose that I could have qualified that as an antenna that works! 8^) Some theorists in the late 1940's did some work on the fundamental limits of small antennas. There are one or two papers available on the web if you search for "small antennas" with google. People who think they can make a small (in terms of a wavelength) single radiator antenna, with good efficiency, and a large bandwidth, that doesn't have to resort to feedline radiation to achieve its aims, would do well to read these papers before making themselves look silly by claiming the impossible. It would seem that way to me. From the description, I got the visualization of a hollow tube, with perhaps three main parts. A center conductor, which would be the helix. outside of this would be a vertical wire running from top to bottom. I would assume these to be ground wire, and serve as half of the capacitor function. There might be some version of little hats attached to the helix from top to bottom as the other part of the capacitor(s). Will it work? "work" is so subjective..... - Mike KB3EIA - |
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