"What kind of modulation should I use on a UHF oscillator so that I can receive the signals from a microphone on a cell phone and have it reproduced?"
The cell phone is not just a radio signal receiver. The station with which it communicates (ERB) is encrypted by the company providing the services and uses its own digital modulation making it impossible for both interference and data capture or cell phone use. There is the possibility of using applications that make use of Wi-Fi communication for this purpose and in this case one can think of a transmitter that uses the appropriate protocol for this type of communication.
