Lets use process of elimination
1. Is your coax cable running from the back of your converter box out of the "RF Out"?
2. Is the other side of your coax cable running to your TV to "RF In" or "Antenna In"?
3. Confirm that your TV is set to channel 4
4. Plug your antenna into the back of your converter box in the input that's labeled "RF In"
5. Confirm that the back of your converter box doesn't have a dip switch that needs to be set to channel 4, if it does, set that switch to 4.
6. Make sure that both the TV and converter boxes are powered on. Most converter boxes require you to press the power button first.
See this thread if you would like to see a video demo of a converter box installation:
http://www.dtvusaforum.com/converter...ox-videos.html