[VHFcontesting] Loop Yagi theory

jon jones n0jk at hotmail.com
Mon Oct 3 16:51:14 EDT 2016


Zack and Bill's explanations were good regarding Mark's question. The polarization of an antenna depends on the orientation of the electric field. Recall electromagnetic radiation (radio waves) consists of an electric field and magnetic field.


>From N6NB regarding polarization of quad loop yagis:


"Although the quad loops are square or circular, the antenna is linear in polarization, not circular.  If it is fed at the bottom, the antenna will be horizontally polarized.  Feed the antenna on either side for vertical polarization (and then mount the directors vertically, not horizontally."

http://n6nb.com/quagi.htm


 - Jon N0JK

________________________________


Hi does anyone know of a web site that explains why loop yagis are horizontally or vertically linearly polarized ?


73

Mark S
VE7AFZ


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It's basically the same idea as with a quad antenna. A loop (either
circular or square) fed at the bottom or top has current peaks at the
feedpoint and opposite side of the quad or loop, and voltage peaks at the
side points (90 degrees to the feedpoint). This is similar to a horizontal
dipole antenna, which has horizontal polarization.

There's more to it than that, but that's the basic idea.

73, Zack W9SZ









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