You can build a transmitter to play digital TV, DVDs, videotapes and games on a TV without AV inputs easily.
Connect an F-plug to both ends of a coaxial cable. Connect one end to the output of an RF modulator or VCR, and the other to an indoor aerial. Tune the modulator and TV to the same channel. The range is approximately 5 feet without a booster.
This method gives a better picture. Connect an F-plug to one end of a coaxial cable. Connect this end to the output of an RF modulator or VCR, and the other to the antenna input of a TV. If the TV has a 3.5mm antenna input, use an RF to 3.5mm adaptor. Tune the modulator and TV to the same channel.