English: Monopole spark gap radio transmitter which Guglielmo Marconi developed in 1896. It consists of a long wire monopole antenna (A) with a spark gap (S) to ground, with an induction coil (T) powered by a battery (B) through a telegraph key (K). When the key is pressed down, the induction coil applies a string of pulses of high voltage to the antenna. Each pulse charges the antenna with electric charge, which is discharged by a spark through the spark gap. Each spark causes an oscillating standing wave in the antenna which quickly dies out, and the antenna radiates the energy as a damped radio wave.