Dish may provide you locals via satellite, but they won't be HD. You will need a UHF antenna and run it to that 811 tuner box. You would need to check in the Dish and Sat forums to see if maybe you could just run it into a multiswitch (?) if you already have one so you don't have to run another coax to the 811.
Your sony is a KF, not a KDF, so it does not have an ATSC tuner built-in, but your 811 does, although I don't know anything about how it would compare to something like the LG LST-4200A DTV tuner that I use.
I said UHF. NBC is on channel 10, which is still VHF, but the ChannelMaster 4228 UHF antenna picks up 10 fine, so others might as well.