THEORY
FORMULAS - TABELS - CALCULATIONS
Use a calculator and convert dBm to Watts.
Use your (Microsoft) Calculator and select the scientific mode.
  Example:     dB value = 44 dBm
 Use the MOUSE or the Calculator KEY and clear (C) all previous entries!
 1. Type in 44 and divide the (dB) value by 10.
 2. Select INV and log.
 3. The Indication is 25118.86... milliwatt (mW).
 4. Divide the indication by 1000. The result is 25.11... Watts