0 0 votes The critical frequency of an ionospheric layer is $10 \; \mathrm{MHz}$. What is the maximum launching angle from the horizon for which $20 \; \mathrm{MHz}$ wave will be reflected by the layer? $0^{\circ}$ $30^{\circ}$ $45^{\circ}$ $90^{\circ}$ Analog Communications gate1996-ec analog-communications continuous-time-signals numerical-answers + – admin 263 views answer comment Share Follow Add Sync Questions Print 0 reply Please log in or register to add a comment.