I just got my antenna hooked up yesterday so I could finally get digital and HD programming. All the local channels are shown in 4:3 except when they are in HD. However, ABC has a different format. I don't know what it is. It's in the middle of 4:3 and 16:9. What is it and why do they use it? And what is enchanced TV? I was watching Monday Night Football and it said it is shown in enhanced TV. Thanks.