What is Space Wave Communication? Explain.

Explanation

A space wave travels in a straight line from transmitting antenna to the receiving antenna. Space waves are used for lines -of -sight (LOS) communication as well as satelite communication .At frequencies above 40 MHz , communication is essentially limited to line-of -sight paths . At these frequencies , the antennas are relatively smaller and can be placed at heights of many wavelengths above the ground. Because of line-of-sight nature of propagation , direct waves get blocked at some point by the curvature of the earth as illustrated in Fig . If the signal is to be received beyond the horizon then the receiving antenna must be high enough to intercept the line-of-signt waves .
If the transmitting antenna is at a height `h_(T)` , then it can be shown that the distance to the horizon `d_(T)` is given as `d_(T) = sqrt((2Rh_(T)))` where R is the radius of the earth (approximately 6400 km) . Similarly if the receiving antenna is at a height`h_(R)` , the distance to the horizon `d_(R)` is `d_(R) = sqrt((2Rh_(R)))` .
With reference to Fig . the maximum line-of-sight distance `d_(M)` between the two antennas having heights `h_(T)` and `h_(R)` above the earth is given by `d_(M) = sqrt((2Rh_(T))) = sqrt((2Rh_(R)))`
Television broadcast , microwave links and satellite communication are some examples of communication systems that use space wave mode of propagation .