yea I have a built-in ATSC/NTSC Tuner on my TV. The regular (SD) channels would be 2, 4, 5, 7, 9, 11, 13, etc. and the HD versions of those (DT) would be 2-1, 4-1, 5-1, etc..
but since they installed the new HD receiver, even when I turn it off and I try to view locals it says "no signal."...