I found the folowing formula to find the focal point of a dish but its for a parabola, f=D²/16C where D is diameter and C center to top of dish. Is there a formula like this for elliptical dish? Also should i use the normal mounting point which is angled and does not hit the dish perpendicular but rather at a slight angle like the first dish in the illustration or make a mounting point out of 3 metal rod to hit the perfect center?
Also, i know because i read it, that the f/D ratio for 2.4Ghz should be between 0.25 and 0.55 but why?
