John, thanks for the correction. You're absolutley right, 50 Ohm is for antennae cable such as RG8 or RG213 and smaller diameter RG-58 for internal distribution racks between antennae hubs and receivers; 75 ohm is for video runs ONLY on standard RG-59.
DOH.
Thanks for keeping me accurate & honest. I have corrected my earlier post.
JvB