A/V to RF.

[Oldskool]

Not really sure what you mean by an RF modulator. You might need to be a bit more specific.

A/V means audio/video. So basically any connector that outputs audio and video is an A/V jack. Even RF. Some people call composite (yellow,white,red) A/V - for some reason. Kind of like how people say that their NES top loader is A/V modded. What they mean is that it has Composite audio and video. Not sure when or why they ever got mixed up.

[Compute]

You want to build an rf modulator to convert your a/v to RF? Unless you're real handy and/or have the parts already, it's going to cost you more than buying one off the shelf.

If you're dead-set on having a fancy case, you might just re-case an existing RF modulator. Otherwise an older VCR with a bunch of different circuit boards and through-hole parts would be a good source for a board with an RF modulator circuit.

RF is pretty much A/V, but the signals are combined and modulated for radio frequency (RF) as if for radio broadcast. The difference here is that the signal is not going to be broadcast, so it is weak enough that a cable is necessary to carry to signal to your television. Because of the amount of conversion and un-conversion involved, this signal ends up being less clear than the other ways of sending a signal from device to TV (i.e. composite AV, S-video, component, etc).

[Greg2600]

Not sure what you're getting at? But if you're looking to go from Composite/RCA connection to RF/Coax, there are cheap RF Modulators for that. I have one of those, if you need one. If you're trying to go from an RF connection (2600 for instance) and hook up to the TV's Composite/RCA jacks, then you need a de-modulator. Those have never been made cheaply, costing hundreds of dollars for some reason. However, most people use an old VCR to get that to work.