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#1
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Has anyone taken a look at this antenna? I heard the designer on 75 last
night working a CT0, he says his is 18 foot in diameter. His buddy was running a 6 foot version and 200 watts and worked the DX as well. He claims that it is a "minium reactance antenna" thus the name. http://www.smeter.net/wb4ene/mra-antenna.php |
#2
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I am only guessing, but there isn't a backpack/portable version of that
antenna available, is there? And, I just looked at my car, where would I mount that? Or, is that the kids playhouse, and it obscures the view of the antenna? grin Regards, John -- I would like to point out, I do appreciate the "Been there--done that!" posts. Indeed, now your observations, comments and discourse should be filled with wisdom--I am listening!!! "Fred W4JLE" wrote in message ... Has anyone taken a look at this antenna? I heard the designer on 75 last night working a CT0, he says his is 18 foot in diameter. His buddy was running a 6 foot version and 200 watts and worked the DX as well. He claims that it is a "minium reactance antenna" thus the name. http://www.smeter.net/wb4ene/mra-antenna.php |
#3
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Fred,
I seem to recall a simular antenna made by 'MFJ' or 'Hygain', maybe? No idea how 'well' it worked. 'Doc |
#4
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On Wed, 13 Apr 2005 13:35:42 GMT, 'Doc wrote:
Fred, I seem to recall a simular antenna made by 'MFJ' or 'Hygain', maybe? No idea how 'well' it worked. 'Doc I'm having a hard time seeing the "minimal reactance" part of this design. Looking at the plot of S11 it looks pretty much like any other antenna with a single resonance. It has "minimal" reactance at resonance and is highly reactive elsewhere. |
#5
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I'm having a hard time seeing the "minimal reactance" part of this
design. Looking at the plot of S11 it looks pretty much like any other antenna with a single resonance. It has "minimal" reactance at resonance and is highly reactive elsewhere. It looks to me as if this is a member of the "Super C" antenna... short, relatively low radiation resistance, and a lot of top-loading capacitance. There's an article or two in one of the early ARRL Antenna Compendium collections (#1 or #2) which analyzes the "Super C" approach, compared to a short vertical with a more traditional capacity hat made of straight wires. The analysis seemed to add up to "Probably not worth the trouble and money", as a similar efficiency can be achieved more easily and less expensively with the traditional approach. There's a *lot* of metal in the MRA, and at the price of aluminum this month I doubt it's a project I'd start. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#6
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![]() Dave Platt wrote: I'm having a hard time seeing the "minimal reactance" part of this design. Looking at the plot of S11 it looks pretty much like any other antenna with a single resonance. It has "minimal" reactance at resonance and is highly reactive elsewhere. It looks to me as if this is a member of the "Super C" antenna... short, relatively low radiation resistance, and a lot of top-loading capacitance. There's an article or two in one of the early ARRL Antenna Compendium collections (#1 or #2) which analyzes the "Super C" approach, compared to a short vertical with a more traditional capacity hat made of straight wires. The analysis seemed to add up to "Probably not worth the trouble and money", as a similar efficiency can be achieved more easily and less expensively with the traditional approach. There's a *lot* of metal in the MRA, and at the price of aluminum this month I doubt it's a project I'd start. Yea, but put in on a rotator and add some horses and it could double as a merry-go-round. :-) ac6xg |
#7
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In article ,
Jim Kelley wrote: Yea, but put in on a rotator and add some horses and it could double as a merry-go-round. :-) Y'know, I had *started* to add a paragraph to my posting suggesting that this antenna could be disconnected from its feedline and used as a jungle gym, but decided that it was a trifle irresponsible to do so. Too much potentially-sharp metal edges to have around the kiddies, and there's always that chance that Dad might accidentally key up QRO at the wrong moment. "Honey, I smoked the kids!" :-) -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#8
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He was saying that his patent was about to be issued, he also mentioned
something about a fractal top. At that point I QSYed. "Dave Platt" wrote in message ... I'm having a hard time seeing the "minimal reactance" part of this design. Looking at the plot of S11 it looks pretty much like any other antenna with a single resonance. It has "minimal" reactance at resonance and is highly reactive elsewhere. It looks to me as if this is a member of the "Super C" antenna... short, relatively low radiation resistance, and a lot of top-loading capacitance. There's an article or two in one of the early ARRL Antenna Compendium collections (#1 or #2) which analyzes the "Super C" approach, compared to a short vertical with a more traditional capacity hat made of straight wires. The analysis seemed to add up to "Probably not worth the trouble and money", as a similar efficiency can be achieved more easily and less expensively with the traditional approach. There's a *lot* of metal in the MRA, and at the price of aluminum this month I doubt it's a project I'd start. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#9
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Fred W4JLE wrote:
He was saying that his patent was about to be issued, he also mentioned something about a fractal top. A balanced fractal top hat cannot be beat!!! :-) That's one of the things that fractals are good at. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#10
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On Mon, 11 Apr 2005 21:02:01 -0400, "Fred W4JLE"
wrote: He claims that it is a "minium reactance antenna" thus the name. http://www.smeter.net/wb4ene/mra-antenna.php Hi Fred, A simple glance at the SWR chart reveals it is in fact a Maximally Reactive Antenna - at least the initials are preserved. 73's Richard Clark, KB7QHC |
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