What is the major factor that makes coaxial cable less susceptible to noise than twisted-pair cable?

Answer 1

A coaxial cable is shielded from electrical interference signals whereas UTP (Unshielded Twisted Pair) cable is not. The random twisting with which UTP is manufactured works very well, however, in locations where the interference levels are relatively low, because its method of construction ensures that any interference affects both wires in the pair equally. It should also be mentioned that STP (Shielded Twisted pair) cable is also available and is sometimes specified for LANs (Local Area Networks) instead of coaxial cable. But the much greater volume of coaxial cable sold means that coaxial cable prices have been kept very competitive with STP. As STP tends to be more tricky to install - its shield has to be very carefully and correctly terminated at each end - coaxial tends to be used more than STP where noisier-than-normal interference conditions are present at a particular site. Since the 1990s NIC (Network Interface Card or Component) equipment has had extra logic cicuits within it to reject ambient interference much more effectively than equipment which was designed in the previous 20 years, so nowadays UTP can be used more extensively in locations where only STP or coaxial cable would have had to be used before. So, in relation to LANs in normal non-industrial office and domestic buildings, this exam question is now almost obsolete! However coaxial cable is still necessary to carry LANs in difficult environments such industrial plants; hospitals; undergound railway and road tunnels and mines; on board ships and aircraft, etc. and must also be used to carry signals for radio, televison, video and other applications which run at much high frequencies and bandwidths than LANs.

Answer 2

Coaxial cable has a thicker shielding than most other cables.