To calculate dB (power)

• dB = 10*log(x/y)

• 3dB = 10*log(2/1)

• 10dB = 10*log(10/1)

• 13dB = 10*log(20/1)

• 20dB = 10*log(100/1)

• 33dB = 10*log(2000/1)

• 1dBm = 100mW / 1dBW = 1 Watt