Subject : Principle of Communication Engineering

Topic : Introduction to Electronic Communication

Difficulty : Medium

• Ground wave propagation is a process in which radio frequency propagates along the surface of the Earth for the communication purpose.
• Low frequency and medium frequency of the electromagnetic spectral region are mainly used for the propagation of the electromagnetic radiations through ground wave propagation.
• Since these waves travel along the surface of the Earth, they are also called as Surface wave propagation.
• Ground wave propagation of electromagnetic radiations consists of line of sight, reflected and surface waves. Line of sight radiations travel directly from the transmitter antenna to the receiver antenna, without getting affected by the locality.
• Ground reflected radiations are the ones which get obstructed and hence reflected by the obstacles while propagating along the path.
• Surface wave radiations tend to follow the curvature of the Earth while propagating.
• Collection of all these radiations along the surface of the Earth is known as ground wave propagation.
• The obstacles along the path of propagation of the radiation render loss of energy and increase in the attenuation level of the signal.
• The intensity of the radiations drops with distance due to its absorption by ground.
• Frequency is also a factor which affects the propagation of the electromagnetic radiations through ground wave propagation.
• As the frequency increases, the signal radiation becomes weaker as the absorption of the radiations by ground also increases and therefore ground wave propagation is possible for the waves with low frequency, nearly 2MHz.

• Thus ground wave propagation of electromagnetic radiations is mostly used for short distance radio communications. The below given Fig.1 depicts the various types of radiations along with ground wave propagation.

  

  Fig1. Types of radiation waves in Ground wave propagation