Interesting read about the Smart LNB - it's the one that I've read as having a very good performance but never tried it personally. I've tested a few combinations of LNBs/feedhorns/dishes and here's what I've found.

Channel Master 1.2m dish

For this, I find that a well adjusted Black Ultra 40mm LNB works best for me. I have also tried a Black Pro C120 with the original CM feedhorn (transparent cap), a single BU converted to fit C120 and a twin BU converted to C120. None of the conversions deliver a better result than the unmodified BU. Signals were at least 0.5dB better there. So, for now the CM feedhorn is lying in the garage unused...

The conversion was a good one as it allowed me to adjust the skew of the LNB on the C120 flange (pic below).

Fibo 1.2m dish

The other dish I played with was the Fibo 1.2m Gregorian. I originally had it fitted with the Black Pro C120 to the original Fibo feedhorn and it was OK and better than the Channel Master with the BU but the BU on Fibo absolutely trounced the Black Pro. Signals were at least 1dB up across the range of frequencies and many weak channels that never locked became lockable.

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