Question

A transmitting antenna at the top of a tower has a height $32 \,m$ and the height of the receiving antenna is $50 \,m$. What is the maximum distance between them for satisfactory communication in line of sight (LOS) mode ?

• A. 55.4 km
• B. 45.5 km
• C. 54.5 km
• D. 455 km

Answer 1

Answer: (B)

45.5 km

Answer 2

$d_{T}=\sqrt{2Rh_{T}}=\sqrt{2\times6400\times10^{3}\times 32}$
$=202\times 10^{2}\,m=20.20\,km$
$d_{R}=\sqrt{2Rh_{R}}=\sqrt{2\times 6400\times 10^{3}\times 50}$
$=25.3\,km$
$\therefore d=d_{T}+d_{R}=20.2+25.3=45.5\,km$