Saw cables like this on Amazon. There are some which takes usb power like the 2nd link. HDMI to RCA Cable, HDMI to RCA Converte,1080P 5ft/1.5m HDMI Male to 3-RCA Video Audio AV Cable Connector ...

>RCA fittings are about $2 each, and do not require soldering. Well this is one of the problems. Making a 3xRG-6 cable would cost $12 in fittings, and at that point, you could buy a 50' composite ...

The cable connects your iPod, iPhone or iPad to a TV's RCA jacks. It has a 30-pin dock connector that fits into your iPod, a USB connector, and yellow, red and white audio/video RCA connectors.