Unguided Media
Different unguided media used in communication are follows:
1. Microwave: Microwaves are radio waves that are used to provide high-speed transmission. Both voice and data can be transmitted through microwave. Data is transmitted through the air form one microwave station to other similar to radio signals.
Microwave uses line-of-sight transmission. It means that the signals travel in straight path and cannot bend. Microwave stations or antennas are usually installed on high towers or buildings. Microwave stations are placed within 20 to 30 miles to each other. Each station receives signal from previous station and transfer to next station. In this way, data transferred from one place to another. There should be no buildings on mountains between microwave stations.
2. Communication Satellite: Communication satellite is a space station. It receives microwave signals from earth station. It amplifies the signal and re-transmits them back to earth. Communication satellite is established in space about 22,300 miles above the earth. The data transfer speed of communication satellite is very high.
The transmission from earth station to satellite is called uplink. The transmission from satellite to earth station is called down-link. An important advantage at satellite is that a large volume of data can be communicated at once. The disadvantage is that bad weather can severely affect the quality of satellite transmission.
3. Mobile communication: Mobile communication is radio-based network. It transmits data to and from mobile computer. Computers can connect to the network via wired ports or wireless connections.