Characteristics of ionospheric propagation at high latitudes and their impact on communications systems

The success of beyond-line-of-sight HF data communications is dependent on the characteristics of the ionospheric medium. At high latitudes, these characteristics typically change rapidly with time. This paper describes the static and dynamic characteristics of two high latitude links, one sub-auroral and one trans-auroral. These results have important implications for the design of data modems and, automatic link establishment techniques.