Ok I will assume you do NOT have a matrix switch like I do. This is a box with many buttons (BOMB we call it) that can send ANT to one tv while sending SAT to another and CABLE to a 3rd.
Most (Well many) Have a simple wall plate. USUALLY near the main TV it has a TV antenna jack, a 12 volt outlet an LED light and a switch.
Assuming you are the ORIGINAL owner.. Turn the switch off for park cable.
IF YOU ARE NOT the original owner.. Well try turning the switch off. it may or may not work. If it does not work pull that wall plate (2 screws) there should be 3 cables tonnected to the rear.. If there is a "Loose" cable. or a cable that has been extended to who knows where. it connects to the CENTER port on the back of that switch.