This tool calculates the deciBel (dB) antenna gain from its linear value.
Calculator
- Enter either the linear value of Antenna gain relative to Isotropic or half-wave dipole
- The tool provides both the dBi and dBd values.
🔄 Antenna Gain dB to linear
Formula
GdBi = 10*Log10(Gi)
GdBd = GdBi – 2.15
where
- GdBi is the dB gain relative to an isotropic antenna
- GdBd is the dB gain relative to a half-wave dipole
Background
Antenna gain is a measure of how well an antenna can convert input power into radio waves headed in a specified direction, compared to a reference antenna. It is a key parameter in evaluating antenna performance because it directly affects the effective range and strength of the radio signal.
Antenna gain can either be specified as a linear or logarithmic quantity. As well the reference antenna is either an isotropic antenna or a half wave dipole.
Antenna Gain depends on its antenna factor and frequency of operation.
Example Calculation
A linear gain of 9 (for example) relative to an isotropic antenna gives
GdBd = 7.39 and GdBi = 9.54
Note GdBi = 7.39 + 2.15