It is called an RF video cable. You can find them on Amazon just look up the term RF video game cord or cable .
And RCA cable would be a temporary fix. However you would get a little bit of a loss of signal because of the make up of the center core of the wire, it is a little thicker and has an 8 ohm impedance. The RCA contact on the outside is a little thinner as well versus the thicker contacts on the standard RF cable.