Does your projector have a channel changer/tuner? Can you change from channel 3 to 5? If not, you cannot cook your CATV service directly to your projector.
You need a "tuner".
Do you have a VCR? It is about the cheapest/best way to give you a video output that you can feed your projector.
Another solution: call your cable company about their "digital" box's. These devices let you change channels, and offer SVideo and even Component video outputs. The output of these should feed your projector.
Warning: be prepared for disapointment. Ordinary CATV video looks crappy on larger and larger displays. The video is backwards compatible to the 1940's standard when a television was a 9-inch B&W tube. Blowing it up or displaying it on a modern HDTV or projector simply exposes all the noise/flaws/compression artifacts. A DVD player would be a better source for that projector.
i am my local cable company... lol yea i have a digital box.. but i dont pay for cable.. that is how i was putting it through my projecvtor and they shut my box off becouse i was stealing cable.. lol we dont get it for free.. and i didnt even think aboutt he vcr.. thanks