I helped my girlfriend buy a new TV. She has some older equipment so her DVD player uses composite video. Her VCR only has a F connecter/coax output. And she has her digital antenna plugged in to the antenna input on the new TV. The problem is that I don't know how to hook up both the VCR and the Antenna. Is there some device that will allow me to convert from a coax video signal in to a L/R/Video signal?
That's pretty old-school/low-def, but the way of doing it about 10 years ago was to plug the antenna into the antenna-in on the VCR, then from the out of the VCR into the TV. When the VCR is powered off, it should send the antenna to the TV. When the VCR is on but not playing, you can generally choose sources from the antenna or RCA-In if it has that. For starters though, have the VCR off, as that should pass antenna through.
Advantage - this is super simple... when you want to watch a VHS, no TV settings are changed really other than changing channels - when you want to watch VHS, change to channel 2, 3, or 4 (whichever works, it'll only be one) and hit play - you'll see the tape playing and it'll cut off the antenna channels.