The laptop connection to an older television requires a video adapter cable as well as an RF modulator, which changes composite video to a coaxial signal. The video adapter converts a video graphics array (VGA) port on the laptop into a composite video plug that can hook up to the RF modulator, which is needed for old TV sets equipped only with a threaded coaxial cable jack. Both the adapter cable and the RF modulator are available at electronics stores.
Connect the 15-pin plug on one end of the adapter cable to the laptop's VGA port, usually on the back or left edge of the component.
Insert the composite video plug on the other end of the adapter cable into the matching video port on the RF modulator.
Attach the coaxial cable from the RF output jack on the RF modulator to the RF IN or ANT IN jack on the rear of the television cabinet. The metal ring on each end of the cable turns clockwise around the jacks.