A transmitting antenna at the top of a tower has a height 18 m and the height of the receiving antenna is 32 m. What is the maximum distance between them for satisfactory communication in line-of-sight mode? Given radius of earth is $6.4 × 10^6 m$.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 35.4 km
Maximum distance for LOS communication is -
$d=\sqrt{2Rh_t}+\sqrt{2Rh_r}$
$h_t=18m$ [given]
$h_r=32m$ [given]
$∴d\sqrt{2×(6.4×10^6)×18}+\sqrt{2×(6.4×10^6)×32}$
$=20,240m+15,174m$
$=35.4km$