My Windows Vista PC has a Hauppauge HVR-1600 TV tuner. It has both a cable and antenna input as well as an FM input. I can receive stations via my analog cable system and via antenna from local broadcast stations. I can only receive HD broadcasts via the antenna. Although I can receive broadcasts from both sources it is not possible to set the program guide to provide information on channel listings for both. That appears to be caused by the fact that the registry can only handle one source code. You will probably wish to use the setting for your cable service since there are more channels there.
Microsoft needs to make program changes to handle 2 guides. TIVO has done this with their Model TCD652160 recorder. That unit appears to receive it's program information from the same source as the Media Center.