Question

The critical frequency of Flayer is 50 MHz when angle of incidence is 74°. What is the maximum unable frequency? 

(A) 181.5 MHz 

(B) 191.5 MHz 

(C) 199.5 MHz 

(D) 171.5 MHz

Answer 1

The correct option is (A) 181.5 MHz.

Explanation:

Maximum unable frequency = MUF = f_c sec θ 

f_c = 50 MHz 

θ = 74° 

∴ MUF = 50 MHZ × sec 74 = [(50 MHz) / (cos 74)] = 181.5 MHz