The story of radio waves actually begins with the 19th century exploration into electricity. In the 1860s, Scottish physicist James Clerk Maxwell was theorizing about the wave structure of light and the existence of electromagnetic waves, which he predicted could travel at the speed of light. It took experimental physicists some time to build the equipment necessary to test Maxwell’s theories and generate these waves.
When German physicist Heinrich Hertz constructed this apparatus and successfully generated electromagnetic waves, or radio waves, in the laboratory, he opened the door to further experimentation that led to wireless telegraphy. The key to that door would be the development of a receiver that would prove the existence and usefulness of these waves.