An extension cable is as important as an Antenna
The standard solution to acquiring improved cellular signal strength is to have an antenna placed as high as possible to achieve a line of sight with the nearest cell. In most cases, this means a coaxial cable extension of up to 20m. Any cable extension means loss of signal to and from the antenna and is therefore as crucial as the antenna itself for optimum signal strength.
The most popular coaxial cables are RG174 and RG58. Both can be used with standard RF connectors and are adequate to use when the cable length is relatively short.
Taking a closer look at RG58, this cable has a 1dB loss/m at 2.4GHz, meaning that the signal that arrives at the end of an RG58 cable is about 0.07% of what went in. The low loss cable version of RG58 is LLC200A.
LLC200A has an approximate loss per meter of 0.55dB at comparable frequency. So, when using LLC200A, 12% of the signal appears at the end of a 20m cable. This could well be the difference between using a cable extension with low loss cable as opposed to a standard one.
The difference between a standard and a low loss cable is due to the construction of the cable, including insulating and jacket material (see below table).