System and method for monitoring emissions from a cell phone in a vehicle having a driver side and a passenger side, using several antennas at different locations. A receiver is associated with each antenna and includes at least one amplifier and a rectifier module that converting radio frequency signals to direct current signals. A microprocessor processes the direct current signals received and determines based thereon a phase shift or difference between signals received by two or more of the antennas, which can be correlated to a most likely location of a cell phone being used by an occupant in the vehicle.