dBm is the power ratio in decibels (dB) of the measure power referenced to one milliwatt.  dBm is used to define signal strength in electronic equipment such as our HiBoost amplifiers.  You can think of the dBm as the amount of power an amplifier or antenna’s capable of producing or how much signal is at a site. dB is the relative number of the amount of increase or decrease in signal.  It is a logarithmic calculation.  If an outside signal is negative 90 dBm and our booster is 60 dB then our radiated signal will be negative 20 dBm.