The Bel is named after Alexander Graham Bell, and is the base 10 logarithm of the ratio of two power levels. Originally, the Bel was used to compare two audio power levels in terms of the response to them by the human ear because the human ear responds logarithmically to audio power levels.

In the wireless world DeciBels (or dB) are used as a convenient common unit to convert wireless measurements to. Some measurements that you will see represented as dB are:

A handy reference chart of dBm -> mW equivillents is available on dBmChart.

DrEngelson did say the 'i' in dBi meant current. I believe he was confusing 'I' which normally used as an abbreviation for current in Ohm's Law, V=IR, with the real meaning of 'i' in dBi. It means 'isotropic radiator', which is some sort of theoretical antenna that is useful for comparing against other antennas. A good summary is at -- DonPark <link corrected [CategoryGlossary]

DeciBels (last edited 2007-11-23 18:00:48 by localhost)