Question

Which of the following frequencies will be suitable for beyond the horizon communication using sky waves?

• A. $10kHz$
• B. $10MHz$
• C. $1GHz$
• D. $1000GHz$

Answer 1

Answer: (A), (B)

The correct options are
A $10kHz$
B $10MHz$

For beyond-the-horizon communication, it is necessary for the signal to cover large distance. $10KHz$ signals cannot be radiated efficiently because of the antenna size. The high energy signal waves ($1GHz$ − $1000GHz$) penetrate the ionosphere and escape. $10MHz$ frequencies get reflected easily from the ionosphere. Hence, signal waves of such frequencies are suitable for beyond-the-horizon communication.