Suspension bridge types are present in the majority of larger suspension bridges. Although the earlier types of suspension bridges are suitable only for relatively short spans, all of the 14 longest bridges in the world are suspension bridges (see List of longest suspension bridge spans). Ignoring the possibility of pre-Columbian trans-oceanic contact, there were two independent inventions of the suspension bridge, in Eurasia (probably in China) and in Central and South America. Types of suspension bridge include the following: A pure suspension bridge is one without additional stay cables and in which the main cables are anchored in the ground. This includes most
Coaxial cable other types of radio transmission line is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines. Coaxial cable also provides protection of the signal from external electromagnetic interference. Coaxial cable conducts electrical signal using an inner conductor (usually a solid copper, stranded copper or copper plated steel wire) surrounded by an insulating layer and all enclosed by a shield,