Comment Re:MoCa (Score 1) 608
D-Link, Netgear, etc all make a multimedia over coax converter, they typically allow you to hit 100mbps using existing lines via frequencies boosted way over the TV range (essentially the same way networking via powerlines work).
It really sounds like he doesn't want to pay any money, he just wants to fiddle some connectors together and connect from a UTP equipment to coax. I've seen people to really ad-hoc things over short distances and be able to get buy with high amounts of loss and very slow speeds. To do anything decent you really to deal with signal processing hardware...your never going to get the appropriate voltages, line conditioning, noise handling, etc unless you make your own layer 1 & 2 hardware.
Now you might have luck with playing with something that runs on a more forgiving medium...possibly modifying the antenna controller in a set of older single antenna (non-MIMO ) wireless routers and use the coax between them. But its probably not going to work without a lot of tweaking which puts you back in with dealing with signaling, plus the wireless would have worked over the air; and also this would cost you just as much as replacing the coax, or buying a proper media converter.