I tried to get the files from LiveATC for departures on 23 Just at 1400Z. You are absolutely right. The file category for KOSH del/gnd/dep/atis seems at that time to be blank. I checked other times and the time for 1300 has lots of traffic on it. 1330 is blank. The files for the towers (North, south, north and south) are all inbound traffic. Gnd/tower/approach has clearances and landings on rwy27 but does not seem to have departures. The feeds are provided by volunteers and if no one was recording it, then it won't be there.