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: 141,8144768 mA

The calculation

First you calculate the dB difference in power.

${\displaystyle 35,4-35,1=0,3\$dB}

• Note: the unit is dB not dBm

Calculate the calibrated current to dBmA so we can add the value.

$20*log10(137)\approx 42,73441134\ dBmA$

So after the addition of the power difference the new value is 43,03441134 dBmA.

Calculate this back to mA:

$10^{\frac {43,03441134}{20}}\approx 141,8144768\ mA$

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

Decibel