BUT, is that main feed ALSO in HD? I believe that those PBS subs being carried, are ONLY being carried if the main station is ONLY in SD. Also, I believe those subs are ONLY being carried in MPEG4, even if the main SD feed is in MPEG2.
Chicago's 3rd PBS station is like this as well, while the other 2 ONLY have their main feeds carried, but both are also in HD.