Net Power

Net Power defined as Forward Power minus the Reflected Power This document describes how you should calculate the Net Power correctly.

Given information

Frequency (MHz)	Forward Power (dBm)	Reflected Power (dBm)
201,973	50	30

Question: What is the Net Power?

Answer: 49,95635195 dBm

The calculation

First you calculate the dBm values to linear values.

${\displaystyle 50\$dBm=10^{\frac {50}{10}}\ mW=100\ W} ${\displaystyle 30\$dBm=10^{\frac {30}{10}}\ mW=1\ W}

Subtract the linear values

$Net\ Power=Fw-Rf=100-1=99\ W$

Convert the value to dBm again:

${\displaystyle 10*log10(99*1000)\approx 49,95635195\$dBm}

Power expressed in milliWatt in dB values.

• 1 mW = 0 dBm

• 2 mW = 3 dBm

• 100 mW = 20 dBm

• 1 W = 30 dBm

• 100 W = 50 dBm