Frequency variation of ionospheric absorption at vertical incidence

The results of a series of experimental studies of the dependence of ionospheric absorption on short radio waves in the frequency range 2–9 Mc/s are presented. The variation of absorption, -loge ρ with frequency ƒ follows the law, -loge ρ α A/[(ƒ + ƒL)m] with an average value of m of the order of 1.5. The results obtained are compared with those at other latitudes