Home >> Science & Nature >> Science

How to Convert Decibels to RF Units

The decibel, or dB, is the logarithmic ratio comparing two quantities. One quantity is measured and the other is the reference. Radio frequency units such as watts, volts and amperes are measured using decibel notation. Smaller units such as the milliwatt (mW), the millivolt (mV) and the milliampere (mA) are used since they are more practical to work with. Milli is metric for one one-thousandth (1/1000). For power, three dB represents double the ratio; 10 dB represents 10 times the ratio. For voltage and current, six dB represents double the ratio; 20 dB represents 10 times the ratio.

Things You'll Need

Scientific calculator or Windows calculator
Scratch pad (optional)

Instructions

Converting Decibels in Power
- 1
  Use the formula: P2/P1=10^(db/10) where P2 is the measured power and P1 is the reference power.
- 2
  Go to "Start", then "All Programs", then "Accessories", then "Calculator".
- 3
  Click "View" under "Edit" and select "Scientific".
- 4
  Divide the decibels (db) by 10 (db/10); this is the exponent used next.
- 5
  Click on the "10" button with the "x" in the upper right corner; this multiplies 10 by the exponent in parentheses.
Converting Decibels in Voltage
- 6
  Use the formula: V2/V1=10^(db/20) where V2 is the measured voltage and V1 is the reference voltage.
- 7
  Go to "Start", then "All Programs", then "Accessories", then "Calculator".
- 8
  Click "View" under "Edit" and select "Scientific".
- 9
  Divide the decibels (db) by 20 (db/20); this is the exponent used next.
- 10
  Click on the "10" button with the "x" in the upper right corner; this multiplies 10 by the exponent in parentheses.
- 11
  Compare the voltage units using this multiplier.
Converting Decibels in Current
- 12
  Use the formula: I2/I1=10^(db/20) where I2 is the measured current and I1 is the reference current.
- 13
  Go to "Start", then "All Programs", then "Accessories", then "Calculator".
- 14
  Click "View" under "Edit" and select "Scientific".
- 15
  Divide the decibels (db) by 20 (db/20); this is the exponent used next.
- 16
  Click on the "10" button with the "x" in the upper right corner; this multiplies 10 by the exponent in parentheses.
- 17
  Compare the voltage units using this multiplier.

Science