Abstract:
The solar flared during 1977 September have been analysed in the light of their SPA effects produced in VLF signals over long propagation paths. The analysed data show an apparent linear relation between log (sec χ) and ∆h. Directional effects on the propagation path for VLF signals has been noticed. Observed SPA's data reported by Murubashi et al. (1982) have been utilized for ionospheric D-region during these flares.
