This document provides guidance on use of radio spectrum for the purpose of communication with Unmanned Airborne Vehicles (UAVs), the airborne part of Unmanned Aircraft Systems (UAS). It is also applicable to Remotely Piloted Aircraft (RPA), the airborne part of Remotely Piloted Aircraft Systems (RPAS). Anything involved with spectrum use by UAS of any type for any non-payload purpose is within the scope of this Guidance. Use of spectrum for payload is out of the scope of this Guidance. It is motivated by challenges to providing access to radio-frequency spectrum to achieve the aspiration to expand the scope of UAS operations to fly further, higher, more often and for a wide range of purposes.