How do signal boosters automatically power down when approaching affected base stations

Consumer signal boosters are designed to automatically power down or cease amplification as they approach any affected base station[4][9][10]. FCC regulations require all cell signal boosters to auto-detect oscillation, and take corrective action immediately when it is detected[1]. Newer cellular boosters made after 2014 automatically reduce power or shut down entirely to prevent interference with nearby cell towers in the event of signal oscillation[5].

Automatic gain control (AGC) adjusts the booster automatically to compensate for signal fluctuations[3]. When the booster adjusts its attenuation automatically, the outside donor antenna and inside broadcast antenna attenuate in equal amounts[3].

If a signal booster is exposed to too much gain, it will shut down entirely rather than cause oscillation with the cell tower[7]. Most signal boosters can reduce their gain by around 20dBm[11]. If critical attention is not given to the installation of antennas and oscillation occurs, it can shut down the booster until there is no amplification at all[11].