There are a number of factors you need to look at.
If you have cable, you'll have to check your local listings. Yahoo has a good listings web site, all you need to do is type in your state, zip code, and if you have cable, satellite, etc. You could also search for TV listings web sites.
If you have DISH Network, like I do, it's channel 176. I don't know what the channel for Comcast is, though. But if you have cable, you're going to have to look up your local listings. Hope this helps.