I am using DSR-920 and 6 foot dish, but have BSC-621 LNBF (C and Ku).
The digital DCII channel on G3-600 comes in just fine.
C band is both digital (DVB and DCII versions) and analog.
Your 922 receiver has 2 ports on the back, one for C band and one for Ku band. You'll need to run a 2nd cable back to your dish and put on a LNB or LNBF that has both C and Ku on it. Then you'll get some C band digital.
How are you moving your dish?