I receive my HD channels over the air -- I live in the City of Albany (near St Peter's Hospital), so I'm pretty close to the transmitters. I've been using my antenna for several weeks since I dropped my TW digital service.
Yesterday (Fri., Sep. 3), WRGB was pixellated to the point of being unwatchable. Today (Sat., Sep 4) the signal is not coming in at all. WNYT is also degraded, but the other channels come in strong as ever.
On Sunday 9/5 WRGB looks OK to me (it's always the weakest of my stations) but WCWN is gone. Since they're both owned by the same company, my guess is planned maintenance. Any official word would be posted in WRGB's DTV forum (http://www.cbs6albany.com/share/forums/?plckForumPage=Forum&plckForumId=Cat%3a956f56b5-71a2-4dfe-b14a-069902858962Forum%3ab6afd8cf-3c20-4e52-9d58-7b633a4e87ff) but probably only if someone asks there.