Efforts were made to use radio in World War I, but the technology proved unreliable. Wireless sets were available in battlefield trenches, where they were reserved for emergency communication in the event of cut telephone and telegraph wires. Where are radio waves located on the electromagnetic spectrum? Radio waves are located at the low-frequency end of the electromagnetic spectrum, beneath gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, radar waves, microwaves, and television waves.