How to convert coaxial to RCA?

You need a tuner (the cable you have is intended to feed into a TV which has a built in tuner). The easiest way is to use a cable box or satellite receiver both take coaxial input signals and output standard video and audio signals. But this requires you to pay for the box/receiver. You can do the same on the chap with a VCR (it has a TV tuner built in) or buy a stand alone TV tuner. In these days of digital TV you really need a tuner capable of handling a digital signal and outputting standard video and audio. I use an HD satellite tuner (I pay for HD service) and watch HD video on my projector. SD TV will work ... but it doesn't look very good on a big projector screen. I suggest you subcribe to HD cable and get the cable box to put on the existing cable.

If you have just standard def service - use a VCR which lets you tune to a particular channel. But crappy standard def service was designed to fill a nine-inch screen. Blowing it up on a projector will look horrible. (Like looking at newsprint under a magnifying glass.) You need to upgrade to HD service with a box then you use an HDMI cable for high-def video and optical audio output.

The "Cable" or RG6 coax you see is either for a Antenna or Cable itself. I believe TV's have "tuners" in them that convert the signal from the RG6 to a workable signal to view a picture of. The projector you have is merely just that a projector (unless you have one I never heard of). It needs some sort of signal that has been converted to play. Hope this helps!

Check to see if your amp can receive the coax signal and then output the signal to the projector thats my two cents

I'm not sure you can. usually the tv converts it. I don't think the projector can do that.