Question

please define sky wave propagation with advantages and disadvantages

Answer 1

The signals are reflected from ionized layer of the atmosphere known as Ionosphere. Here signals can travel number of hops, back and forth. 
Example: SW Radio



Advantages of Sky wave

Following are the benefits or advantages of Sky wave:
➨As it utilizes reflective property of ionosphere available above earth at higher frequencies, it is most simple mode of propagation and provides continuous support in communications. 

Disadvantages of Sky wave

Following are the disadvantages of Sky wave:
➨Ionoshere is present near or far during night time and day time respectively. Due to this, Sky waves can travel longer or smaller distances. 
➨Transmitter signal travels multiple hops before reaching the receiver. This reduces signal strength considerably if distances are larger between transmitter and receiver antennas.