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.
To run a prediction
The two points on Earth may be specified by typing latitude and longitude or by searching through a set of pre-defined cities and geographic areas provided with the program.
To run a prediction, the solar flux index is also needed. This number is found on radio broadcasts of National Institute of Standards and Technology radio station WWV at eighteen minutes past the hour, every hour. There is a relationship between the Sun's solar flare activity and the reflective properties of the Earth's atmosphere at HF frequencies. This number describes that relationship.
The program takes these geographic points, the solar flux index, propagation models, estimates F-layer maximum usable frequency and E-layer minimum. The results are presented in a text table describing which frequencies are most likely to "get through".