Parabolic dish focal ratios & spillover angles
From Alex Pettit 2-3/12/2025:
Its related to the Feed Beam Pattern and the Shape ( f/D Depth ) of the dish.
“All” f/D 0.35 dishes perform similarly regardless of diameter
When it is impractical to install a large choked cylindrical Feed to narrow the beam,
the next option is to DEEPEN the dish as a Shield.
Look at the Depth of this 12 meter dish !! Looks like it was build as an f/D 0.25
