Title: Microsoft Word - Conversion_table_WvS.doc Author: John Wilkes Created Date: 9/21/2004 1:07:41 PM RF Calculator: Wavelength, dBm, dBuV, W, dBuV/m, mW/cm^2, pJ/cm^2, V & VSWR This RF calculator has been developed by Compliance Engineering as a resource for individuals involved in EMC and RF compliance measurements. The following table provides conversions for wavelength (from frequency), VSWR (from forward and reflected power) and various other useful conversions. Try our […] If, for example, you have a circuit or a device that combines the power of one signal of 10 dBm (10 mW) with the power of another signal of 13 dBm (20 mW), the result is 10 mW + 20 mW = 30 mW which is 14.8 dBm. There is no way of doing this directly in dBm, you have to convert both powers in Watts, add them together and convert them back in dBm. Multiply the corresponding voltage according to the formula by the power factor, the current and the root of three. For example, if you have a 220V (Linea-Line) refrigerator with a power factor of 0.8, and a current of 5 Amps, you should multiply 220 × 0.8x√3 × 5 and obtain 1524.20. 220 × 0.8x√3 × 5) = 1524.20.