Range to station
I thought the simple equation was :
Square root of the height above the station or facility times 1.23 equals range available.
I.E at 2500 feet altitude the range is ...square root of 2500 = 50 X 1.23 = 61.5 Nautical miles.
NB the 2500 feet altitude assumes the radio facility is at sea level. Adjust if the height of the station is above sea level.