Hi everyone, i need make for 5ghz a/n link a circular dual polarization waveguide.

i start building a standard single polarization "cantenna" and i need to know if second probe (90 degree) is placed at same distance from reflector as first probe or twice distance (any formula?).

Antenna will be conected to a ubiquiti rocket M5, in 5,9 ghz feeding a ubiquiti´s nanostation oval reflector.

I want link two locations un line of sight +-25km away. One location have already a powerbeam installed.
You have a formula, web page for some guide or an example?

Thnks in advance