I maintain a page on my blog that focuses on MilCom in the coastal Georgia area, but there is some information on it that should help you out for the Robins AFB area. You should be able to hear activity from the Bulldog MOA on 343.750, which is to the southeast of Robins AFB. F-16s from Shaw AFB and McEntire JNGB regularly train in it and the F/A-18s from MCAS Beaufort use it as well. JSTARS is based out of Robins and the ALC for F-15s, C-130s, C-5s, and C-17s is at Robins.
Not all of the information on this page will be applicable for central Georgia, but some of it should be. Good luck and good listening!
https://kf4lmt.wordpress.com/milair/