I wonder if there's a way to use a short-range radio signal on a public band (like CB, if that still exists) to do local sharing at crowded places. Can the radios in iPhones and typical Android phones even do such a thing?
Cell phone radios are purpose built to save space, expense, licensing, and energy. They can only communicate using the specific frequencies and technologies (GSM, CDMA, WiFi, etc) that they were designed for.
