I think you now have basic digital cable over coax.
The Slingbox Pro-HD's digital tuner supports Advanced Television Systems Committee (ATSC) and clear QAM (unencrypted digital cable) broadcasts. To use the internal digital tuner you'd use "Cable service (without a cable box)". To use standard analog over-the-air (OTA) then you'd use "Antenna". Finally if you have a set-top tuner which broadcasts on channel 3/4 then you'd use "External box (cable box, satellite receiver, DVR, etc)." These options are available in "ANT IN" video source configuration of the Setup Assistant within the Slingplayer.