Thread: Loop fed yagi
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Old February 12th 11, 02:41 PM
ka7niq ka7niq is offline
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First recorded activity by RadioBanter: Feb 2011
Location: Tampa florida
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Quote:
Originally Posted by Dave Platt View Post
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.

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Dave Platt AE6EO
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