Dude, you definitely don't need to know a single radio call before UPT. For each phase, you will have academics that will teach you everything you need to know. Enjoy your time before pilot training, then show ready to work. Academics is 6 weeks before you ever hit the flight line. Study radio calls during contact. There will be time to study for instruments and a bunch of sims. Don't waste your time/money.
If you look at everything now, you will most likely 1) not understand it, or B) learn it wrong. No one there to answer questions, possibly outdated pubs, etc. There is a lot gained with academic instructors and probably more from your senior classes that can explain everything to you when you're there. Once you hit the flight line you'll have IPs sitting in the flight room to answer questions.