How do i change to channel 2.1 or other ".1" for hi def? Antenna only tv?

Answer 1

Your TV needs to have a digital tuner, because those are digital channels. (Note: digital, but not necessarily high-def)

First do a channel scan, so that the TV can find them.
In most TVs, Ch+/Ch- on the remote should go to the digital channels as well. The remote should have also a . (dot) or dash key. Use that to enter the decimal part.