Question
Download Solution PDFIn the space wave propagation of radio waves if the height of both the antennas is h and the radius of the earth is R, then the maximum line of sight distance is equal to the:
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFCONCEPT:
Space wave communication:
- A space wave travels in a straight line from the transmitting antenna to the receiving antenna.
- Space waves are used for line-of-sight (LOS) communication as well as satellite 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 the line-of-sight nature of propagation, direct waves get blocked at some point by the curvature of the earth as illustrated in the figure.
- If the signal is to be received beyond the horizon then the receiving antenna must be high enough to intercept the line-of-sight waves.
- The maximum line-of-sight distance dM between the two antennas having heights hT and hR above the earth is given by,
\(\Rightarrow d_M=\sqrt{2Rh_T}+\sqrt{2Rh_R}\)
Where R = radius of the earth
EXPLANATION:
Given hT = hR = h
- The maximum line-of-sight distance dM between the two antennas having heights hT and hR above the earth is given by,
\(\Rightarrow d_M=\sqrt{2Rh_T}+\sqrt{2Rh_R}\)
\(\Rightarrow d_M=\sqrt{2Rh}+\sqrt{2Rh}\)
\(\Rightarrow d_M=2\sqrt{2Rh}\)
- Hence, option 3 is correct.
Last updated on Jul 4, 2025
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