This tool computes the Antenna Gain using:
- Antenna Factor (units: dB/m)
- Frequency of operation (units: Hz/kHz/MHz/GHz)
Antenna Gain Formula
Gain (dBi) = 20*Log10(9.73/(λ*(10)AF/20))
- λ = Wavelength = c/f, where c is the speed of light and f is the frequency
- AF = Antenna Factor
It is the ratio of the electric field E (units: V/m or μV/m) to the voltage V (units: V or μV) induced across the terminals of an antenna.
The units are dB-per-meter or dB/m.
 Wikipedia Antenna Factor