What is transmission media? Discuss the microwave transmission?
Answer: – Transmission media is the path way by which network entities use to connect each other. Computer transmission media includes cables and wireless technology that allows network devices to connect each other. Transmission media cannot guarantee that other network devices will understand a message it can however, guarantee a message delivery path.
Transmission media is mainly divided into two categories like physical wiring system and wireless system. In physical wire, copper wire is used but in wireless system, electromagnetic wave is used. Physical wire is for short distance transmission while wireless system is used for long distance communication on major drawback in physical wire that it can disturb due to various causes such as rodent or terrorist’s activities while this problem not occur in wireless system.
Physical wire is further divided into three different categories such as twisted pair cable, coaxial cable and fiber optic cable. In both twisted pair cable and coaxial cable, copper wire is responsible to carry signals from one end to another end but in fiber optic cable light wave passes from one end to another end. A copper wire career loss signals after carrying signal up to 5 or 10 kilometers while light wave signal can carry up to 100 kilometer without using of any amplification copper wire cable is responsible to transmit both analog and digital signal while fiber optic is responsible to carry only digital signal instead of analog signal speed of fiber optic cable is much faster than copper wire cable.
In a twisted pair cable one or more pair of cable twisted per six inch. Out of two cable, one is used for carrying signal while other is used for ground twisted pair cable is sometimes also called unshielded twisted cable because copper wire is not shielded into a plastic insulator while a plastic protecting cover is used to protect both copper wire. In a coaxial cable, central copper wire is shield within plastic insulator and a plastic cover surrounded over plastic insulator. And a copper mess is rounded over plastic cover. Central copper wire is responsible to carry signal and copper mesh is used for ground. In a fiber optic cable, signal are transmitted through core and cladding. Core is upper layer of inner surrounding while cladding inner layer of surrounding. In both ends of fiber optic a LED (Light Emitted Diode) is used to conversion of signal from analog to light signal as well as light to analog signal.
Microwave is a directed to light-of-sight radio transmission. For long distance communication, microwave radio transmission is widely used as an alternative to coaxial, twisted pair or fiber optic cable. It is used to wideband communication systems and is quite common in the telephone system. Television transmission also utilizes microwave transmission, because microwave transmission is above the 1 gigahertz (GHZ) frequency band and provides the capacity required for video transmission.
The high band width gives small wavelength and the smaller the wavelength, smaller one can design the microwave antenna. The antenna size has significant implication for distributed data processing system. The transmission towers with parabolic antennas can transmit beam to another antenna 20 to 30 miles apart. The transmitted radio beam is focused narrowly to the receiving antenna. The higher the tower the greater the range with a 100 meter high tower distance of 100 km between towers are feasible. Longer path than this can be achieved by the use of repeaters. These links can easily carry 1000 mbps or so and are usually multiplexed between long distance telephony, TV program distribution and data. These towers can be seen through cities and country side.