Just did a couple of things here to look into the situation, and a few things dawned on me on why you are having issues this weekend.
There is no snow on the dish, its completely clear.
However, there are 2 possible scenarios that could be causing the issue (depending on what time you saw them):
1: Sun outages. Normally, when CBS switches us to the backup bird, you don't see a glitch. On the HD side, however, when we switch transponders, you do see a loss of input signal indication if the HD switch is on.
2: If you saw this loss of input signal indication at the start of the game, it is because the HD receiver is switching transponders.
I don't know what time you saw the loss of input signal today, but I did get a call at home from our MC in Indy about 1:30 yesterday afternoon about it. I just talked to them again today about it and they reminded me of the sun outages this week. I'm leaning towards that being the problem. You'd see it at least twice as CBS switched us back and forth from the Primary transponder.
We're keeping a close eye on it right now to see if that is indeed the probelm or if its something else.