This Recommendation provides methods for the prediction of the reliability and compatibility of HF radio systems. The ITU Radiocommunication Assembly@ considering a) that the reliability of a radio system is defined as the probability that a required performance is achieved; b) that reliability is a figure of merit of performance; c) that compatibility is a measure of the degradation caused by interference to the performance of a radio system; d) that predicted reliabilities and compatibilities are valuable in the selection of preferred combinations of antennas (including@ where necessary@ their design optimization)@ frequencies and necessary transmitter power to achieve a desired performance@ recommends that the following methods for calculating the various types of reliability and compatibility should be used in the planning and design of radio systems.