What would cause a digital cable channel to be anamorphically squashed? (1 Viewer)

Has anyone had this happen?

I've been watching my local Retro TV affiliate through Knology Digital Cable. A few days ago, the signal changed from 4:3 to something like a pillarboxed square. It looks like I'm getting a signal for a 16:9 television that's being squeezed to fit the 4:3 screen of my TV. Oddly enough, this is the only channel that's being affected.

So where along the chain would this problem be caused? At Retro TV? My local station? My cable provider? And what can be done to correct it?

do you have an hdtv with a hdtv sourceor reciever?

No, none of my equipment is HD.

If it's only the one channel, contact your cable provider. It sounds like they're accidentally transmitting a wide-screen image without letterboxing it.