Cell phone boosters or Bi-Directional Amplifiers are a technology that strengthens radio signals used by cell phones.They do this by utilizing an antenna that receives the initial signal and then rebroadcasts that signal in a more focused manner. After the signal is received by the outdoor or the “donor” antenna it is brought indoors via a low loss coaxial cable.The signal booster than takes the signal and strengthens it and sends the strengthened signal to an indoor antenna where it is broadcasted to devices in the area.
This can be done in the opposite direction as well. Meaning that when you are near a booster with your mobile device it sends its signal to the nearby antenna which then amplifies it and sends it out via the outdoor antenna. Also as an added benefit, these boosters increase your phone or other devices power and they also allow them to run more efficiently with some devices gaining up to 65% more battery life.