You are limited by the range of the 5.8GHz command link between the master (pilot) and slave (camera) RCs. This will be somewhere between 20 and 40m. Ideally, you should be close together in normal verbal range without the need to shout. You would need ear pieces and microphones if you are planning to use mobile phones; both pilot and operator will have their hands full. While the phone signal may not affect the 2.4Hz and 5.8Hz bands, it is worth considering switching off the Bluetooth and wifi features. Small radio handsets should be avoided as they use the 2.4GHz band.