Is it possible to actively use a S3 tivo without subscribing to digital cable? I have a nice OTA antenna that gets a great HD signal and don't want to pay for the extra hd package from comcast. Currently I get channels 2-97 of standard cable. Would I be able to use the Tivo to program the guide without having cable cards or will I have to setup manual recordings? If I have to setup manual recordings, and am using an OTA antenna, will the S3 tivo still be able to record two shows at once? I will still be subscribing to the tivo service.