JSTARs is the E8 / Airborne Battle Management platform from the 116 ACW/Robbins AFB, GA. They actually will use two callsigns. The ATC c/s is usually PEACH xx. The Air Combat Controller, or what they refer to as the backend , may use the c/s STARGATE.
AWACs is the E3/Airborne Warning and Control System from the 552 ACW/Tinker AFB, OK. The ATC c/s is usually SENTRY xx. The Air Combat Controller, or backend will use the c/s DRAGNET, BANDSAW, CHALICE, or DARKSTAR. These c/s may be followed by a letter foxtrot/kilo/victor.
Both of these platforms are usually players at RED FLAG at Nellis AFB. Hope that helps...
David