The box I use replaces the tuner in the TV . Works on channel 3/4 I think .
I picked up a Zenith box , works good once you get it set up .
http://www.zenith.com/dtv/ info on how to set one up ...
The antenna might need to be adjusted some for best picture . Digital pics is either good or nothing I have found . The unit will have a signal strength indicator built in , just got to find it .
Good luck
Barney