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Loop fed yagi
Has anyone used or tried an antenna like this ?
http://www.g0ksc.co.uk/intro-lfa.html Called a loop fed yagi. It is mostly a VHF beam where the driven element is a loop. The loop is flat with the boom so it looks similar to an extra element with the ends joined. There is an example of a 5 element 50 mhz beam. It takes about the same ammount of aluminum to make a 6 element beam. Would this antenna be more of an advantage over a 6 element beam of say the K1FO type ? |
Loop fed yagi
Has anyone used or tried an antenna like this ?
http://www.g0ksc.co.uk/intro-lfa.html Called a loop fed yagi. It is mostly a VHF beam where the driven element is a loop. The loop is flat with the boom so it looks similar to an extra element with the ends joined. Hmmm. It's somewhat similar in philosophy to the "quagi" (Yagi-type directors, with a quad-loop driver and reflector, but I think it's even closer to being a Yagi with a folded-dipole driven element (you can think of a folded-dipole DE as being a very-wide-and-shallow loop). You can follow a progression of these designs, from a Quagi (which uses a square loop DE), to this "loop-fed Yagi", to a standard Yagi fed with a folded dipole driven element, and then to the WA5VJB "Cheap Yagi" with its half-folded dipole driven element. All of these use the folding or looping of the driven element to raise the feedpoint impedance, which would otherwise usually be well below 50 ohms. The shape of the driven element controls the type of impedance transformation you get. -- Dave Platt AE6EO Friends of 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! |
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Loop fed yagi
On Feb 11, 1:58*am, (Dave Platt) wrote:
Has anyone used or tried an antenna like this ? http://www.g0ksc.co.uk/intro-lfa.html Called a loop fed yagi. *It is mostly a VHF beam where the driven element is a loop. *The loop is flat with the boom so it looks similar to an extra element with the ends joined. Hmmm. *It's somewhat similar in philosophy to the "quagi" (Yagi-type directors, with a quad-loop driver and reflector, but I think it's even closer to being a Yagi with a folded-dipole driven element (you can think of a folded-dipole DE as being a very-wide-and-shallow loop). You can follow a progression of these designs, from a Quagi (which uses a square loop DE), to this "loop-fed Yagi", to a standard Yagi fed with a folded dipole driven element, and then to the WA5VJB "Cheap Yagi" with its half-folded dipole driven element. *All of these use the folding or looping of the driven element to raise the feedpoint impedance, which would otherwise usually be well below 50 ohms. *The shape of the driven element controls the type of impedance transformation you get. -- Dave Platt * * * * * * * * * * * * * * * * * AE6EO Friends of 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! Dave I agree with you on the evolution from a folded dipole. Wonder what this design does for gain and F/B. How do check an N connector to see if you put it together right? Draw any blood lately? Jimmie |
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