Which of the following frequencies will be suitable for beyond-the horizon communication using sky waves? (1) 10 kHz (2) 10 MHz (3) 1 GHz (4) 1000 GHz
Correct options are A) and B) For beyond-the-horizon communication, it is necessary for the signal to cover large distance. 10 KHz signals cannot be radiated efficiently because of the antenna size. The high energy signal waves (1 GHz − 1000 GHz) penetrate the ionosphere and escape. 10 MHz frequencies get reflected easily from the ionosphere. Hence, signal waves of such frequencies are suitable for beyond-the-horizon communication
