Absorption of HF radiowave (20 MHz) in F-region of the ionosphere

Abstract

By considering the theoretical work of S Chapman and C G Little [<i>J Atmos & Terr Phys</i> (<i>GB</i>), 10 (1957) 20] the non-deviative absorption for 20 MHz radio frequency in F-region of the ionosphere has been calculated using the electron-neutral collision frequency obtained by S N Ghosh and P K Sarkar [<i>Indian J Radio & Space Phys</i>, 7 (1978) 46]. The calculated electron-neutral and electron-ion collision frequencies due to different sets of observed electron density and temperature profiles in the altitude range 200-400 km vary from 4.6 x 10³ to 1.0 x 10²s^-1 and from 8.3 x 10² to 0.91 x 10²s^-1, respectively. The total absorption for 20 MHz radiowave in the same altitude range calculated for the same electron density and temperature profiles vary between 0.35 and 0.84 dB. These absorptions agree with cosmic radio noise absorption (i.e. 0.25-0.94 dB) for 20 MHz in F-region measured during January-October 1964 at Delhi by S B S S Sarma et al. [<i>Indian J Pure & Appl Phys</i>, 8 (1970) 529].