A simple approach is remove the enclosure from the lnb , cut off the feedhorn. Here is a picture of one of my first antennas. The copper pipe is way too long in this picture, but it worked. After some test, i modified the enclosure to fit again. An even simpler approach is to leave the enclosure on and drill a hole in the front cap of the lnb, just with the outer diameter of the copper pipe. Then stick the pipe through that hole and gently push it into the horn. The lnb you use is not critical, as long as it is a lnb with a xo . There are a lot of examples floating around on this reflector.
73, Martin
Thank you very much, is the length of the waveguide actually a non-essential item? If it is then I understand and I will push on.