For some reason my MiniTioune fed from a Megasat Diavolo LNB on a 1.8 meter PF dish has started to show the unhappy face and an average of 2.9dB LNA gain. The Diavolo is home modded to take a 25Mhz LO from a Leo Bodnar GPSDO. I tried putting the original Bullseye LNB back and get the same results. I realise I need to look at attenuating the LNB level, but meanwhile can anyone tell me if such a signal level can also cause a sudden rash of noise on the MiniTioune noise graph and a de-sensitising on low level signals?
The thing I find odd is this level of LNA gain has seemingly only started recently. Maybe it's just atmospheric conditions, the impact of which on 10GHz is a bit of a mystery to me I'm afraid..