[Tech-Assist] STL problem now critical

[Cowboy]

On Wednesday 28 March 2012 08:13:38 am Dave Dunsmoor wrote:
> I would think that the focal point should be figured the same as a  
> satellite antenna.

 A dish reflector is a dish reflector.
 It's either spherical, or parabolic.

 There's only two formulae for figuring the focal length.
 One for spherical, and one for parabolic.
 For parabolic, f = D2 / 16d where f is focal distance, D is
 the diameter of the reflector, and d is the depth of the dish.
 For spherical, the focal length is half the radius of the sphere.

 Manufacturing tolerances might cause this to vary slightly.
 ( slightly, as within an inch or so )


-- 
Cowboy