OETA replays the previous nights PBS primetime the next day on OETA Okla, the .2 subchannel, so tonight's Masterpiece Classic with Downton Abbey will be replayed tomorrow night at 8pm central on OETA Okla which is the 125W Ku feeds. The replays on Okla are SD though with tonight's showing on the main OETA channel being HD.
I was watching yesterday night (Thursday) Downton Abbey, a new episode from this last Season Four different from that I saw last Sunday (I think this episode will be broadcasting on PBS next sunday). Here´s the data from the transponder wher I saw it last night :
Sat: AMC21 125W
Transponder : 12180/V/30000
PID : V81 / A 8276 [Dolby D] / P81
FEC : 1/ 4
SID : 5
Resolution : 1080i
Don't Know if this is transmitted allways on Thursdays at 9PM ET. This is first time i see it.
I hope it helps.