Do you mean news feeds back to the affiliate stations? Then KU is the primary band that's used, but there are some feeds that are on C band. The best times to view the news feeds are in the morning AM news times or the evening news times. Or when there is a big breaking story happening. The format used is DVB/MPEG digital.
If you are referring to the big network (NBC, CBS, FOX, etc) feeds of their prime time shows back to the affiliates then the band is a mix between C and KU band. PBS and NBC are on KU and the rest are on C band. Some are clear some are encrypted.
Optimal dish size for KU would be in the 1-1.2 meter range for some of the more complex signals, otherwise around 90 cm would work. For C band although a 6 foot dish would probably get about 1/2 the sats, 8 foot would be minimal for most channels. Some more complex signals would require 10 afoot dish.
There's a lot to learn about the hobby. Here are some of the links I have found to be useful:
Rick's Satellite Wildfeed and Backhaul Forum
Ricks Satellite Wildfeed and Backhaul Forum
SatelliteGuys Forum (Free to air discussion)
Free To Air (FTA) Discussion | SatelliteGuys.US
After my move to Florida I still have not set up my KU FTA system. But I have in the past had motorized KU dishes up to 1.2 meter and C band dishes up to 12 feet. Started the hobby in 1984 when everything including HBO was in the clear. That was the golden age of Satellite TV before DirectTV and Dish almost ruined the hobby.