The simplest answer is, as far as you can get them, which isn't really very helpful. The affect they will have on each other tapers off as the distance increases, but there will be some affect until that distance gets huge. The key there is, how much is too much till it's acceptable? Good question, and I can't answer that.
The only way I know of minimizing all that 'affecting' is to put one above the other. Doesn't really minimize much, but it makes it symmetrical, sort of, and less noticeable. Not as much of a 'bump'/'clump'/'dump' in spots.
That separation distance is measured in wave lengths. The greater the better, till it gets totally ridiculous. You might be able to get them 10 wave lengths apart, but then how do you feed the @#$ things?
So, basically, it's a matter of maximizing where you can, and minimizing where you can, so that the whole thing fit's inside your wallet. It would be real easy for me to spend your money, so it's a pretty good idea if you do that 'mini/maxi' mizing thingy instead of me, right?
Aw rats! Just buy out the whole neighborhood, doze off all that mess, landscape it of course, remote the radios to the base of the towers and control it all from your easy chair! Ain't no step for a stepper! Lets see... I figure 4 or 5 multi-million dollar lottery wins ought'a handle it. Get busy.
- 'Doc
The bill is in the mail.