Q9 of 26 Page 1

Distinguish between ‘sky wave’ and ‘space wave’ modes of propagation. Why is the sky wave mode of propagation restricted to frequencies up to 40 MHz?

In the sky wave mode of propagation, the signal from the transmitter is reflected off the ionosphere at a certain degree to be received by the receiver.


In space wave mode, the waves are directly transmitted between the transmitter and receiver in straight lines.


The sky wave mode is restricted to frequencies less than 40 MHz as anything greater than that penetrates the ionosphere and is not reflected by it. Hence, that signal is lost.


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