Why is this in the computer section?
Anyway, don't exchange the box just yet! First, can you access the converter's menu? Because mine automatically comes up with the "no signal, call customer service" message, but I can access the menu fine -- so the hook-up is not the problem. If you can access the menu, let it autosearch for you, because mine can't be used until I do this. If you get the "weak antenna signal message", refer to the user manual to find out how to check your antenna signal strength; if it's in the weak range, you have to buy a better antenna, most likely from the official source: http://www.accessHD.tv
You can always exchange the box and repeat the process. Getting the "no signal" message is a good indicator that you've hooked everything up right, especially if it's accompanied by a customer service number. You can email me at email@example.com
and I'll try to help you troubleshoot the problem if you like. I'm up all night.