> I read an article by Christman K3LC where he uses a different non
> quadrature phasing relationship and gets more gain and a tighter
> pattern on the azimuth and the elevation pattern. He has an article in
> ON4UN Low Band DX'ing handbook and in May 1992 QST. Problem is that he
> does not show how he arrives at the non quadrature phasing numbers of
> 0, -116, -232 etc.
>
> Can anyone supply more data on how these results were
obtained?
Gain comes from pattern interference, it's like squeezing a balloon
with your hands to make it stick out more in one direction. In order
to obtain gain, you have to remove energy from a direction that has
considerable energy by forcing a null in that area.
When you put a null where there already is a null, there is little or
no power to be removed. When you put a null straight off the back,
it is a null in one single small area and has the lowest gain of any
null position.
If you move the nulls slightly off the back the null forms a "cone"
where energy is removed. Since a wider area of radiation is
removed or reduced, the "gain" is higher. That is why two end-fire
elements fed 120-140 degrees out-of-phase have more gain than
two elements with the 180 minus-spacing-in-degrees phasing that
fires a point null directly off the back.
In your case, you have the equal of (2) two-element arrays one in
front of the other each with nulls off the back, and are trying to
multiply the two patterns together. Naturally trying to remove
energy where there is no energy doesn't help much.
73, Tom W8JI
W8JI@contesting.com
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