Equation for Received Power

 Pr = PT + GT + GR - 20*Log(F) - 20*Log(R) - 32.44 - LA    (dBm)

Where:
Pr    = Received power level, dBm
PT   = Transmitter power, dBm
GT   = Transmitter antenna gain, dBi
GR   = Receiver antenna gain, dBi
F      = Frequency, MHz
R     = Transmitter-Receiver separation distance, km
LA    = Sum of all additional losses, e.g. transmission line, weather, etc.