Oh yeah.. an old topic..
IIRC, Arc-net used rg-62 @ 93ohms..
thin-net/ethernet/10base2 used rg-58 or a enhanced rg58 @ 50 ohms.
tv antennas and CCTV use rg59/rg6/rg11 @ 75 ohms
catv/satellite uses rg6/rg11 @ 75 ohms..
59 generally has greater loss, and more importantly, less shielding than rg6 or rg11. this is important, as catv uses frequencies that are also used for other services, and if allowed to leak, can interfere with radio communications or other broadcast services.
a quick chart of some common coax types, from greater --> less loss.
50 ohm: rg174, rg58, rg8/rg213/rg214
75 ohm: rg178, rg59, rg6, rg11
93 ohm: rg180, rg62
