Francois LX1DU spend a lot time to improve the gain off the original Procom dishes. Inspired by a professional NEC Cassegrain system and some earlier publications from Martin G7MRF *) in the year 2000, he went to work.
Because he has no CNC capacity, he made everything by hand on a normal lathe and milling machine. After several readings at its test fixture, he found an optimal shape for his sub reflector.
Illumination of the dish is done with a conical horn and reflected by the convex shape of the sub reflector. Measurements showed the following results; He found an overall efficiency for the original setup of ~ 47%. A modified dish with lx1du Krückstock illumination did ~ 62% and the setup with Cassegrain brought ~ 74%. The values are measured with a stable 76 GHz source and the percent values gives a clear picture of the achieved improvement.
Best wishes, Francois LX1DU.
*)
http://www.g3pho.free-online.co.uk/microwaves/casseg.pdf