Home  ›  11th Syllabus  ›  Transmission Media Unguided Media  ›  Unit 202

Transmission Media Unguided Media

, ,

Unguided or Unbounded media

Microwave

Microwave signals are used to transmit data without the use of cables and the signals are similar to radio and television signals and are used for long distance communication. Microwave transmission consists of transmitter, receiver and atmosphere.

In microwave communication, parabolic antennas are mounted on towers to a send beam to other antennas. With a 100 meter high tower, distance of 100 km between towers are feasible.
Advantages of Microwave Signals
  • It is cheaper to implement than guided media
  • It offers freedom from land acquisition rights that are required for laying, repairing the cables
  • Offers ease of communication over difficult areas.
  • Microwave have the ability to communicate over oceans
Disadvantages of Microwave Signals
  • It is insecure communication
  • Provide reduced signals 
  • It is affected by the weather effects like rain, thunderstorm etc.
  • Cost of implementation and maintenance is high

Radio wave

The transmission making use of radio frequencies is termed as radio wave transmission. All radios, however, use continuous sine waves to transmit information (audio, video, data). Each different radio signal uses a different sine wave frequency and that is how they are all separated. 

Advantages of Radio wave signals

  • Radio wave transmission offers mobility
  • It is cheaper to implement than guided media it offers freedom from land acquisition rights that are required for laying, repairing the cables
  • Radio wave offers ease of communication over difficult areas

Disadvantages of Radio wave signals

  • It is insecure communication
  • It is affected by the weather effects like rain thunderstorm etc. 
Satellite 

A communication satellite can be seen as a microwave repeater in space. It is equipped with a number of devices called transponders, each of which listens to some portion of the electromagnetic spectrum, amplifies an incoming signal and re-broadcast it at another frequency.
Advantages of Satellite Signals 
  • The area coverage of satellite is quite large
  • It is easy to implement than guided media 
  • Heavy uses of intercontinental traffic makes the satellite commercial attractive.
Disadvantages of Satellite Signals
  • Technologically limitations prevent the development of large, high gain antennas on the satellite platform.
  • High atmospheric losses above 30 GHz limit carrier frequencies
  • High investment cost and insurance cost associated with it 
  • Due to low antenna gains, over crowding of available bandwidths occurs

Subscribe to: Post Comments ( Atom )