You kill me! Google Atari 800. It has a thin cable coming out the back which is RF combined audio/video (mono, I think) with an RCA end on it, not F-Type threaded coax. I'm not making this up.
On the other hand, there is a "monitor" port on the side of the computer which is female DIN5 with (I've read) chroma, luma, composite, audio (mono) and ground pins. One could probably build an adapter cable for either composite out or S-Video out. One reference I found suggested that chroma isn't actually available on this model.