Mention three different modes of propagation used in communication system. Explain with the help of a diagram how long distance communication can be achieved by ionospheric reflection of radio waves
(i) Ground wave or surface wave propagtion.
(ii) Sky wave propagation or ionospheric
(iii) Space wave propagation / Line of sight
When radio waves (frequency range 3 MHz to 30 MHz), emitted from the transmitting antenna, reach the receiving antenna after reflection from the ionosphere which acts as a reflector for radio waves the corresponding mode of propagation is known as sky wave propagation.