Radio engineers must consider the interaction of electromagnetic waves with the…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
Radio engineers must consider the interaction of electromagnetic waves with the ionosphere when planning communication systems.
(i) Explain qualitatively how the ionosphere affects the propagation of waves with frequencies below 30MHz compared with waves in the gigahertz range.
(ii) A short-wave broadcast station transmits at 15MHz. Calculate its wavelength and state whether its signal is likely to be reflected by, or pass through, the ionosphere.
(iii) Geostationary satellite communication typically uses an uplink frequency of 4.0GHz. Find the corresponding wavelength and comment on whether this wave will be affected by the ionosphere in the same way as the signal in part (ii).
(iv) Using the results obtained, justify the choice of the microwave band for satellite television links instead of the high-frequency (HF) radio band.