Question

For sky wave propagation of a 10 MHz signal, what should be the minimum electron density in ionosphere

• A. ~ 1.2 × 10¹² m^–3
• B. ~ 10⁶ m^–3
• C. ~ 10¹⁴ m^–3
• D. ~ 10²² m^–3

Answer 1

Answer: (A)

~ 1.2 × 10¹² m^–3

Answer 2

The critical frequency of a sky wave for reflection from a layer of atmosphere is given by

$f_{c} = 9({N1/2}_{\max}$

⇒ $10 \times 10^{6} = 9({N1/2}_{\max}$

⇒ ${N{{\widetilde{\left( \frac{10 \times 10^{6}}{9} \right)^{2}}}^{12}}^{- 3}}_{\max}$