Trans-Equatorial Transmissions at Very High Frequency.
Abstract
Long range VHF transequatorial propagation (TEP) experiments between Greece and Southern Africa on 34, 40 and 45.1 MHz, in progress since 1967, have an equinoctial character regarding occurrence and strength. Studies of fading characteristics and topside electron density profiles lead to the conclusions that phase coherent signals are most likely at least 2-hop great-circle F-transmissions, while other afternoon and evening types, including flutter, which is strongly related to equatorial spread-F, are off great-circle supermodes involving two reflections from the F-layer without intermediate ground reflection. The transmissions have a strong solar-geophysical relationship with a close sunspot number dependence. Correlation with sudden ionospheric disturbances indicates periodic solar dependent defocussing of TEP signal by the lower ionosphere. The combined effects of neutral winds and the position of the magnetic equator control seasonal behaviour. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1973
- Accession Number
- ADA054193
Entities
People
- E. H. Carman
- M. P. Heeran
Organizations
- University of Botswana