Apply with general type 144-146 MHz VHF or narrow band handy transceivers, can receive the frequency of 800-900 MHz cellular telephone. To achieve the high stability and profit, it employs the microwave technique, GA-As FET and crystal oscillation circuit design without antenna. It can still receive weak signal comes from cellular phone; if connect with 900 MHz antenna to the outdoor or outside of the car. Various signals will not be missed.