Restlager Gitterantenne 19dB

What is 'dBi'?
Gain indicates how effectively the antenna is able to collect the energy in a certain direction. It is defined as the ratio, measured in dB, between the signal strength in a certain direction and the signal strength that would be achieved with a fictitious (isotropic) antenna that radiated equal power in all directions. To indicate that the reference is the isotropic antenna, dBi is used here