Yer confusin' me now, Mr D! When you mentioned an LNB I assumed you were talking about a satellite receiver... I suppose having a built in amplifier power supply is no bad thing, though. Not everyone is being bathed in RF energy like wot you are!
I've helped 2 friends recently, who on moving into previously occupied homes, found that they couldn't get any picture. In both cases it transpired that the houses had external amps, and the power supply box had been taken by the last owners...