Assessing the circuit reliability of an h.f. sky-wave air-ground link

Factors which govern the circuit reliability of a long-range h.f. sky-wave link are discussed with particular reference to the relationship between circuit reliability, median received signal-to-noise ratio and operating frequency. Representative cases are analysed and quantitative relationships are obtained for these parameters. Consideration is given to the implications of the findings on the design and operation of h.f. air-ground links.