Well, actually, you're watching HD downconverted to SD since it's on an SD monitor. (but I'm sure you already knew that!)
But it's a darn good looking picture on local channels isn't it?
I wish I could come across one of those for my mom back in Arkansas who is freaking out since I put satellite in at her house and the local channels are based out of DFW. She's not thrilled with the rabbit ears pulling in analog signals and her "soap opera" and local news looking fuzzy. It would be cheaper than buying her a new HD or SD TV with the off air tuner built in (although that would be easier for her to run).
Nice find!