Not sure if I'm understanding this.
To clarify, as I understand it, TV tuner cards that say 'cable-ready' control the cable-TV box from the PC, switching channels and all that stuff. From what you said, I'm assuming such PCI/PCIe cards do not work on satellite-TV tuner (box?). So I'm wondering if there is any equivalent expansion cards or tech that does for satellite-TV what TV tuner cards do for cable-TV? Since I plan on ditching Comcast at first opportunity, it seems like I will not be needing TV tuner card, and can use that slot for a video capture card instead.
All the TV tuner cards I'm looking at that work for both XP Pro & Linux are analog/digital combo (if that is what you mean by 'ATSC'). Not sure just how new any of them are. As regards HDMI, I will only be using VGA, component, or composite connectors. So HD is not a concern.