The type of Communication media in which communication devices sends and receives data signals through air or space is called Unguided media. The data is communicated in the form of wave. Unguided media provides means to transmit data signals but does not guide them along a specific path. The data signals are not bounded to a cabling media. Therefore, unguided media is also called Unbounded media.

This transmission medium is used when it is impossible to install the cables.The data can be transmitted all over the world through this medium. The examples of unguided media are:

Microwave
Satellite Communication
Mobile Communication

1- Microwave
    In microwave transmission, data is transmitted through air or space, instead of through cables or wires. Microwaves are high frequency radio waves. Microwave uses line-of-sight transmission through space. The line-of-sight means that data signals (or waves) can only travel in straight lines and cannot bend.

The data is transmitted and received through a microwave station. A microwave station is also called relay station or booster. A microwave station contains an antenna, transmitter, receiver, and other equipments that are required for microwave transmission. Microwave antennas are placed on the high towers or buildings. These are placed within 20 to 30 miles of each other. there may be many microwave stations between the sender and receiver. data is transmitted from one microwave station to another. Each microwave station receives signals from previous microwave station and transmits to next station. In this way, data is transmitted over larger distances.

2- Satellite Communication
    Satellite communication system consists of a satellite and several earth stations. The communication satellite is a space station. It is approximately 22,300 miles above the earth. Each earth station consists of large dish antenna. It can send and receive data signals.

A satellite receives microwave signals (or messages) from earth station. It amplifies the signals and sends them to another earth station. In this way, data is transferred from one location to another. Data transmission speed of satellite is very fast.

Advantage: The main advantage of satellite communication system is that a large amount of data can be communicated from one country to another.

Disadvantage: The disadvantage of satellite communication is that bad weather can affect the quality of satellite transmission.

3- Mobile Communication
    Mobile communication is a radio-based network. It sends and receives data to and from the mobile computers. The data is communicated through radio signals from one location to another. The Computers can be connected to the network through wireless connections or through wires.

Unguided Media - 3 Main Examples of Unguided Media