Induction coil of a Marconi radio station

The spark gap was used to generate the high frequencies required for wireless transmission. The spark inductor is switched on and off by the Morse key. A capacitor is charged to a high voltage by the induction coil so that the spark gap ignites. An oscillating circuit delivers the energy to the antenna, which in turn emits electromagnetic waves. The German term "Funk", meaning "radio", comes from "Funke" meaning "spark".