For the NB transponder I use a POTY, a very practical single dish solution.
For the WB transponder I noticed that a bare LNB in the focal point (not via the waveguide/pipe of the POTY) gives me 3db extra SNR (MER of the beacon goes from 3 to 6db on a 90cm dish).
Also on the NB I receive 3db more signal on an unmodified LNB.
I also tried with only the waveguide (copper pipe) (without the POTY) on an LNB with the horn cut off: also 3 db less. With or with out lenses, with multiple LNBs, with varying position within the focal point, on a 90 and a 120cm dish.... a bare LNB seems always 3db better.
Also I see that quite a lot DATV WB stations use 2 dishes...is this the reason?
I can imagine the horn antenne that is cutt off results in a loss, but isnt a lense to resolve that, or only partially?
PS I need those 3 db extra for DATV reception, without I only decode the beacon at max 3db