Thread: Loop fed yagi
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Old February 12th 11, 11:41 PM posted to rec.radio.amateur.antenna
JIMMIE JIMMIE is offline
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Default 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