Which term encompasses the complete range of radio frequencies used for communication?

The term that encompasses the complete range of radio frequencies used for communication is "spectrum." In the context of telecommunications and radio communications, the electromagnetic spectrum represents the entire range of electromagnetic radiation frequencies, which includes radio frequencies, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, and gamma rays.

The spectrum is critical in telecommunications as it defines the available frequencies for transmitting various types of data, including voice, video, and other forms of communication. Different frequencies are used for different purposes, and the management of the spectrum is essential for effective communication systems.

While bandwidth refers to the width of a frequency band that a particular transmission can utilize, it is only a subset of the broader concept of the spectrum. Modulation pertains to the techniques used to encode information on carrier waves within the spectrum, and amplitude refers to the height of the waveform, which can relate to signal strength but does not encompass the full range of frequencies. Thus, "spectrum" is the most appropriate term that describes the complete range of radio frequencies used for communication.