In preparation for the second session of the High‐Frequency Broadcasting Conference the Institute for Telecommunication Sciences developed a computer program to assess the impact of planning the frequency bands allocated to the high‐frequency broadcasting service on U.S. broadcasting objectives. The program provides a powerful tool to numerically simulate the performance of high‐frequency sky wave systems operating in both noise‐limited and interference‐limited environments. This paper describes the philosophy behind the design of the program and its various components, such as propagation model, antenna routines, and interference assessment. Examples are given of the application of the program for frequency planning and frequency assignment. Areas in which the program can be expanded to include other services (fixed, mobile, amateur, etc.) operating in the frequency range 3–30 MHz are also discussed.