The Bi Square antenna is described in the ARRL ANTENNA BOOKS.
Each leg is 1/2 wavelength (WL). In the DIAMOND configuration, it is
fed at the bottom, open at the top and the currents in each half-WL
add in phase in the horizontal plane can cancel in the vertical plane.
Changing to a DELTA configuration changes the geometry of the
1/2 WL elements. Feeding at the middle of the bottom and opening
the top would work, but there would be increased vertical radiation
and the effective height would be lower since the bottom wire would
be much closer to the ground and the top wires slope down at a
steeper angle.
If you feed a 2 WL DELTA at one corner and open the other corner,
you end up with a very unsymmetrical 2/3 WL and 4/3 WL combination
of elements. NOT a good idea.
de Tom N4KG
............................
On Tue, 02 Dec 1997 19:38:37 +0800 Tom Osborne <w7why@mail.coos.or.us>
writes:
>Hi gang.
>I just put up a 3 element delta loop fixed East for the 10 meter
>contest.
> I want to hang a bi-square for SE-NW for SA and JA. According to what
>I
>read it has about 5 db gain over a dipole. The apex will be in a tree
>
>about 40 feet up. My question is can I hang it as a delta loop,
>feeding
>in the lower right hand corner and opening the loop directly opposite
>the
>feed point, or does it have to be in a quad loop configuration. The
>info
>I have shows the antenna in a square loop. I would have to hang it in
>a
>diamond configuration as I only have one support point in the tree.
>Thanks and 73
>Tom W7WHY
>
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