Question

Ground/ surface wave propagation is a mode of propagation in which the signal wave glides over the surface of earth, while going from transmitter to receiver. In this mode, there is a loss of power (i.e., attenuation) of signal wave due to diffraction and absorption of signal wave energy by ground. The attenuation of ground / surface wave signal increases very rapidly with the increase in its frequency. Therefore, the ground/ surface wave propagation is not suitable for the propagation of high frequency signal wave and for very long range communication.
Read the above passage and answer the following questions:
(i) What is the frequency range of a signal wave employed for the ground wave propagation?
(ii) For what purpose the ground wave propagation is used?
(iii) What does the study of ground wave propagation imply in day to day life?

Answer 1

(i) For ground wave propagation, the frequency range of signal wave is `530 kHz "to" 1710 kHz.`
(ii) The ground wave propagation is used for local broadcasting as a medium wave broadcast service.
(iii) In day to day life, the ground wave propagation can be compared to the movement of a small child along the
surface of ground. As child can go only upto certain distance on ground and gets exhausted, similarly the
ground wave frequency signal loses its energy while gliding over the surface, of earth and hence can go up to
limited distance. As ground wave propagation is for local broadcasting, similarly, the small child movement
is confined with in home under the supervision of some elders.