Decibel Scale

The Decibel dB is one of the most misunderstood units in elctronics. A Decibel figure is usually quoted with reference to something else. A High Gain Omni-Directional Aerial may be said to have a 3 dB gain. This really means that the Gain Antenna has a gain of 3 dB compared to a standard Half Wave dipole, which is the industry standard 0dB reference. A 3dB gain figure by the way, is a gain of x2

The Decibel Chart that helps with Transmitter Amplifier Gain and Feeder Cable Loss figures