Topband: My Turn For a Brain Pick - Sanity Check

[Tom W8JI]

> I agree. For me, the primary design objectives are maximizing forward 
> gain, beamwidth, and gain bandwidth.  I don't care about F/B.

Null depth is maximum when radiation is equal from the two elements, and 
that occurs with equal effective ampere-feet in the antennas. Equal 
construction antennas require equal current. The current ratio controls null 
depth.

Maximum effective front-to-rear and maximum gain always occurs at some phase 
shift more than 180 - spacing. So if spaced  45 degrees, maximum effective 
F/R (deepest usable null depth off the back) and maximum gain is some phase 
shift more than 180-45 = 135, or in the case of 1/4 wave spacing more than 
180 - 90 = 90.  Phase positions the nulls.

I can't imagine anyone would want one single-point null at zero elevation 
off the back, when they could have a null cone that is just as deep and 
covers a very wide area, or why they  might want less gain, since they get 
more gain with that null cone that gives much better F/R. Perhaps the 
problem is years and years of not wording things properly in our handbooks, 
or not thinking through the problem, has confused people.

73 Tom