Invisible Waves X™ is a personal-computer (PC) -based spectrum analyzer capable of scanning for signals from 9 kHz to 1.8 GHz. The spectrum analyzer is built around a direct-digital synthesizer (DDS) and superheterodyne receiver architecture. The portable monitoring system can work with the firm’s RF Coordinator™ software to identify open and usable portions of RF spectrum as well as the UFO Alert™ software to identify interfering signals. It features ±dB amplitude accuracy over a typical amplitude range of –130 to 0 dBm, connecting to a PC by means of a standard 2.0 Universal Serial Bus (USB) interface. It exhibits 10 PPM frequency stability and provides filter bandwidths from 1 kHz to 50 MHz to isolate and analyze signals of interest.