Hi FC,
I am usually on right after work (4:30/5 p.m. CST) until 7 or so. Then sometimes later in the evening until 10 p.m. CST.
Sometimes folks are online, but not on the AK server, especially if there are less than 4 or 5 AK online. If you check the Battlefield roster list and start sending out friend requests in-game (and log on to Ventrilo), you'll be able to find and join games with other AK.
I think we're all using Ventrilo rather than in-game voice comms.