+The result predicts the most likely operating frequencies and signal
+levels for high frequency (shortwave) radio propagation paths on
+specified days of the year and hours of the day. It is most useful for
+paths between 250 km and 6000 km, but can be used with reduced accuracy
+for paths shorter or longer than this.
+
+The command uses a routine MINIMUF 3.5 developed by the U.S. Navy and
+used to predict the MUF given the predicted flux, day of the year,
+hour of the day and geographic coordinates of the transmitter and
+receiver. This routine is reasonably accurate for the purposes here,
+with a claimed RMS error of 3.8 MHz, but much smaller and less complex
+than the programs used by major shortwave broadcasting organizations,
+such as the Voice of America.
+