The transmission of digital data over 500 km H.F. radio links

Experiments have been conducted to demonstrate the feasibility of using h. f. radio for the transmission of low grade digital data over 500 km paths with bit error rates of the order of 1 in 104. The paper includes a discussion of the factors leading to the poor reliability of short distance h. f. radio links. Equipment developed for the experiments is described and the results are presented. Error rates of the order of 10¿4 will probably be satisfactory for the transmission of raw seismic data, but should lower error rates be required, further work will be necessary to determine the cheapest and most reliable method of achieving this.