A computer program to calculate the coverage and compatibility of HF broadcasts in the presence of noise and interference

The principle of ionospheric prediction methods is to analyse the propagation conditions at several discrete points along the great-circle path between two given terminals. As the main results the highest and lowest usable frequencies or the field strengths at specified frequencies are obtained. These results are strictly valid only at the receiving point or its immediate neighbourhood and are therefore best suited for point-to-point transmission links. Contrary to this, the planning of HF broadcast services requires the knowledge of fieldstrength coverages of usually far extended areas within which the propagation conditions as well as the interference situation may change rather rapidly. In the past computations for this purpose were restricted to some few representative paths due to the excessive computation times. With the appearance of fast prediction programs it is now possible not only to use algorithms for area covering calculations but also to take interference computations into account