Performance of long-distance h.f. radio links terminating in the United Kingdom

The paper presents the results of some analyses made of the performance of radiotelegraph circuits incoming to the United Kingdom. Data are given on the diurnal variations in performance of the Colombo-London and Melbourne-London circuits in sunspot maximum and minimum conditions. An account is given of the ionospheric storm of the 1st¿2nd April 1960, when most h.f. circuits between the United Kingdom and overseas countries were interrupted for long periods. Information is included on the occurrence of sudden ionospheric disturbances over a sunspot cycle. The paper ends with some suggestions on how the accumulated circuit performance data can be used to predict the performance of any existing or proposed h.f. radio circuit terminating in the United Kingdom.