Seattle PBS (9) breaking up?

I've only had my dish hooked up for a few weeks, but the local PBS affliate (channel 9 - KCTS) is constantly breaking up. Anybody else seeing this? It's kind of odd considering that I could get a HD signal by putting an antenna on the roof. You'd think they could get a decent standard definition signal to DirecTV.

Are these type of local station problems typically the fault of DTV or the local affliate?

Dave