Comparison of various methods to control conditions of radio wave propagation in the ionosphere

Conditions of radio wave propagation in the ionosphere can be described and controlled in various ways: 1) a model of the ionosphere, 2) critical frequencies from the vertical sounding data, 3) critical frequencies obtained using the values of the total electron content TEC, 4) maximum observed frequencies for a particular path, 5) values of plasma concentration, measured by satellite. Comparison of these data on real path using the IRI model, global maps of TEC, experimental data of CHAMP PLP shows that the conditions for the propagation of radio waves in the ionosphere can be controlled by an equivalent thickness of the ionosphere.