Question

The field strength due to space wave propagation is E=____

(a) \(\frac{4πh_t h_r}{λd^2}E_0\)

(b) \(\frac{2πh_t h_r}{λd^2}E_0\)

(c) \(\frac{4πh_t h_r}{λd}E_0\)

(d) \(\frac{4πh_t h_r}{λd^4}E_0\)

The question was asked by my school teacher while I was bunking the class.

Question is taken from Radio Wave Propagation in portion Radio Wave Propagation of Antennas

Answer 1

The correct option is (a) \(\frac{4πh_t h_r}{λd^2}E_0\)

The explanation: Space wave propagation reflects frequencies above 30MHz. The field strength due to space wave propagation is \(E=\frac{2E_0}{d} sin⁡ \frac{2πh_t h_r}{λd} ≈ \frac{4πh_t h_r}{λd^2}E_0\)

Here E0 is the field strength due to LOS at a unit distance which depends on transmits power, ht and hr is the height of transmitting and receiving antenna and d is the distance between two antennas.