From: "Andrew de Quincey" <adq_dvb@lidskialf.net>
Searching on the web led me to a philips document ("su1278.pdf") which
describes the optimal settings for the SU1278 on page 10. The driver is
not using these right now. I'm experimenting with the recommended ones,
and they do seem to help.
FWIW, in my Windows driver, I have changed one STV0299B setting compared to
the recommended ones: The recommended AGC2 Reference Level (m2) is 0x19,
but I found that setting it to 0x1F (the maximum) appears to give a better
SNR...
BTW: I also found an issue with low symbol rates: The STV0299B datasheet
says that the gain CFD[6:4] MUST NOT exceed the coefficient e[3:0], as that
may lead to instability. But when you take the recommended STV0299B
settings from the SU1278 datasheet, that is the case for symbol rates <5
MBaud. Since I do not receive any transponders with such a low symbol rate,
I have not been able to verify if there is indeed a problem...
You find some transponders with about 4kSyms/sec on Hotbird if you want
to test.