Therefore the maximum frequency at which radio waves can bounce around the world between the ionosphere and the surface of the earth is limited to ~2f p , depending on the height of the ionosphere for...Therefore the maximum frequency at which radio waves can bounce around the world between the ionosphere and the surface of the earth is limited to ~2f p , depending on the height of the ionosphere for the frequency of interest. where the emissivity of the earth \( \xi=1-|\underline \Gamma|^{2}\), \(\underline \Gamma\) is the wave reflection coefficient of the earth, and T B ' is the brightness temperature of the radiation reflected from the earth into the antenna beam.
