Question

What is space wave propagation ? State its three components.

Answer 1

Hint: Sky wave propagation is one of the examples of radio wave propagation. Radio wave propagation is defined as the nature of the radio waves as they propagate from one point to another or into various parts of the atmosphere.
It can be classified into:
Ground waves propagation
Sky wave propagation
Free space propagation

Complete step-by-step answer:
The radio waves that occur within the 20km of the atmosphere is known as Space wave propagation ie; the troposphere that comprises direct and reflected waves. These waves can travel directly from the earth’s surface to the troposphere surface of the earth hence they are also known as tropospheric propagation. The signals are sent in a straight line from the transmitter to the receiver therefore It is also known as a line of sight propagation.
To prevent loss of signal strength, the height of the antennas and distance between them can be given as:
\[{{D}_{m~}}=\text{ }{{(2R{{H}_{t}})}^{-{\scriptscriptstyle 1\!/\!{ }_2}~}}+\text{ }{{(2R{{H}_{r}})}^{-{\scriptscriptstyle 1\!/\!{ }_2}}}\]
 Where,
\[{{D}_{m}}\]: distance between the two antennas.
R: radius of the earth.
$H_t$: height of transmission antenna.
$H_r$: height of receiver antenna.

Three components of space wave propagation is:
(a) Along the path, radio waves reaching the receiving antenna directly are known as direct waves .
(b) The radio waves reach the receiving antenna after reflection from ground is known as ground reflected wave.
(c) The radio waves reach the receiving antenna after reflection from the troposphere which is known as the Tropospheric wave.

Note: It is widely used in communication systems like a line of sight communication and satellite communication, Radar communication and Microwave linking.
These waves get affected by the curvature of the earth.
The propagation of these waves happens along the line of sight distance; this line of sight system is defined as the distance between the receiving antenna and the transmitting antenna; this distance is also known as the range of communication.