The low-frequency limit for the propagation of radio waves through the ionosphere is discussed. It is shown that reflection and absorption of extraordinary waves can occur well above the F region near the level where | = |H, if the wave frequency is less than |HF2, and if the electron density near this level is not negligible. In these circumstances the low-frequency limit will be determined, by |0F2, and observations of cosmic radio emission at frequencies much below 1 Mc/s are unlikely.

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reflection lowfrequency propagation of radio waves cosmic radio emission

G.R. Elus,.On the propagation of radio waves through the upper ionosphere. 9 (1),51-55.

G.R. Elus,"On the propagation of radio waves through the upper ionosphere" 9

G.R. Elus,"On the propagation of radio waves through the upper ionosphere"