First thing to check is whether you have the power turned on to your roof antenna and that it is cranked up (if it is that style). There should be a small box near the front of the MH with a push button, and an LED light that lights when you press the button. This will energize your antenna. Then make sure your AV box is set for whichever TV you are attempting to use, then place that TV on channel 4. Next you need to go to the TV's menu and do a scan for channels and see what you can receive. The DTV box should also be "on" as it allows you to receive digital OTH channels. IIR you will change channels on the DTV box, and leave the TV on channel 4. Changing out the older TVs for digital flat screens would make this much simpler in the end.