Why is the picture on Birmingham's channel 10 surrounded by a black border?

[Syrinx]

I like to watch some of the programs on PBS. Lately, when I tune in to WBIQ, the picture is surrounded by about two inches of black. My TV is pretty small. Twenty-seven inches, I think.

I haven't bought a hi-def TV yet, and I'm guessing that the problem has something to do with the switchover. But none of the other channels have been affected in this way.

I guess this is a pretty off-the-wall question, but I was just wondering if this is happening with the PBS affiliates in other parts of the state.

My provider is DirecTv, though I'm not sure if that's relevant. Most likely not.

EDIT: To clarify, this isn't letterboxing that I'm talking about, because the black space is on all four sides, not just two.