Here some pictures of my Pi connected to an old colour TV set.
In the 1st photo you couls see the tv displaying a faint LXDE desktop due the flash light, and underside a keyboard, a powered hub, the Raspberry Pi in a cardboard Pummet box and in a tinned steel box a VHF TV modulator, home made.
In the second photo there's a closeup of the Pi and the modulator.
The TV set was the same I was using with my Sinclair QL in 1986. The TV is still used with a satellite receiver, the Sinclair QL unfortunately had a power supply failure and was damaged beyond repair.
The third photo is a photo of the desktop displayed by the TV, showing an image of a test card. Used wide lenses to enhanche the distortion due the cinescope shape.