What is "miniprop"

A DOS application written by Sheldon Shallon (W6EL), Miniprop is used to predict the probability of a high frequency (HF) radio signal path between two points on the Earth's surface. For example, if an amateur radio operator or a shipboard marine radio operator with an HF radio wanted to estimate which frequencies might reach a shore-based station, she could enter data into the program. The software would estimate the best frequencies for the operator to use based on mathematical models.