The output of your DVR is on either channel 3 or 4 so try both. If you connected it with a standard coax antenna wire and are watching on channel 3 or 4 you are not seeing anything like the picture you should. You will need to connect your DVR with the following type of connection in descending order of quality:
1. HDMI (BEST)
2. Component Video (3 RCA plugs) + L/R Audio (2 RCA plugs)
3. Svideo (S video connector) + L/R Audio (2 RCA plugs)
4. Composite Video (1 RCA plug)+ L/R Audio (2 RCA plugs)
Use the one that is compatible with both the TV and DVR. Hopefully the DVR is high definition.