Question

A transmitting antenna at the top of a tower has a height of `45 m` and height of the receiving antenna is `80 m`. What is the maximum distance between them , for satisfactory communication of LOS mode ? Radius of earth ` = 6400 km`.

Answer 1

Correct Answer - ` 56 km`
Here , `h_(T) = 45 m , h_(R) = 80 m`,
`R = 6400 km = 6.4 xx 10^(6) m`
Maximum distance between transmitting and receiving antennas in LOS mode is
` d_(m) = sqrt( 2 R h_(T)) + sqrt ( 2 R h_(R))`
` = sqrt ( 2 xx ( 6.4 xx 10^(6)) xx 45) + sqrt ( 2 xx ( 6.4 xx 10^(6)) xx 80)`
`= 3 xx 8 xx 10^(3) + 8 xx 4 xx 10^(3) = 56 xx 10^(3)`
` = 56 km`