NFL Coaches - Uses a Telex system. Not just any Telex system, but one made just for them. You will not be able to hear anything. OK you can hear it, but you can't understand what is said. It is a digital type system. You will notice behind each bench is a stack of two dishes (beams, whatever) and they are pointed up to the Press box/coaches boxes.
QB's - The NFL has many frequencies licensed to them. I have discovered that they assign a pair to each team (5mhz split as they use it as a repeater). They have a repeater set up, so they can cut the coach off at the times he is not to be able to talk to the QB and turn it back on again when he can. The coach can still be talking, the NFL will just kill the repeater so the QB can't hear him. They use a rolling code vioce inversion on this system. Also something that can not be decoded.
NFL - Some of the other freqs that are licensed to the NFL are used for Game day activities. At the last Steeler game I caught activity on a few of these. Mostly had to deal with pregame show, and other activities. Simplex ops with PL/DPL used
Colleges - At least at the level of Pitt also use a radio system. Very simular in nature to the NFL system. Same thing only different. You can't decode that modulation either. They don't use the same digital modulation (I think)
High Schools - Can run the gammut. They can be as complex as a digital system (Digicom) , Telex systems that you can hear(if your radio has the right coverage) These are analog type systems, UHF VHF freqs (plain old simplex), or UHF freqs using voice inversion. Just about anything goes. Licensed freqs for the school, FRS freqs. MURS freqs, or frequencies in the Telex type systems.
Take a radio and play around. you should find something. I have found searching to be the best bet, although Signal Stalker mode has made a find or 2
Have fun,
Frank
