Predicting Transionospheric Propagation Conditions
ELECTRONICS RESEARCH LAB ADELAIDE (AUSTRALIA)
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A scheme is developed for predicting propagation conditions on transionospheric circuits. The scheme combines a realistic model of F-region irregularity behaviour with thin screen scintillation theory in order to simulate both the mean scintillation index and the probability of the signal falling below a nominated level. Consideration is given to the application of the prediction scheme to transionospheric circuits terminated by a synchronous satellite at 176.5 deg E e.g. MARASAT II and by points on the Earths surface within an area bounded in latitude by 30 N and 65 S and in longitude by 75 E and 270 E. The diurnal and seasonal variations of the probability of disruption of such circuits is investigated under varying conditions of magnetic and sunspot activity. It is concluded that circuits, which terminate in a large and strategically important equatorial region and a small high latitude region, are likely to be disrupted at night. In the equatorial region the possibility of disruption is a highest during the equinoxes, b reduced by magnetic activity and c particularly severe during years of high sunspot activity. The bearing these factors have on the operational use of transionospheric circuits is briefly discussed.
- Radiofrequency Wave Propagation
- Radio Communications