I need to cut off the outer section of the LNB (marked X) to make it easily stick thru the reflector of my helix antenna since I am making a dual band feed. Is the length of the waveguide section in front of the LNB pick up antennas critical?
Can I cut at A, or B freely without affecting any "correct lengths" of the waveguide?
What is the function of the outer part with the larger diameter? Choking section to prevent ground reflections? Impedance matching? Other?