Antenna Power Gain is the ratio of power input to the antenna to power output measured in dBi [decibels isotropic] which is a logarithmic to an isotropic antenna (a perfect spherical or round antenna). According to Cisco, “the greater the dBi value, the higher the gain, and the more acute the angle of coverage.” Decibel or 1/10 of a Bel is a unit to express differences in power. That is, Decibel measurements occur along a logarithmic scale in which each 10 dB increase represents a tenfold increase in signal amplitude, while each 10 dB reduction represents a tenfold reduction.