Don't try using "TV" cable - it's 75 ohm impedance and Ethernet is 50 ohms. If you use 75 ohm cable you'll get all sorts of nasty reflections and probably no workee.
Like SCSI, Ethernet coax must be terminated at each end of the cable, with a 50-ohm termination. There must be exactly two terminators, one at each end, none in the middle.
tony
