Boeing just did a short piece on this, going into the radar testing room, to show the emissions from a cell phone, and how some are over the limit and could affect equipment, and that some can get into synch with each other and amplify the waveform.
Most people dont understand that the sensors are all over the aircraft, not just up front.
Boeing explained that the newer aircraft, and ones that have advertised WiFi service, have been shielded....