Hertz and Marconi: A comparison between the apparatus of their landmark experiments

We all know that Heinrich Hertz [Hamburg, Germany, 1857 — Bonn, Germany, 1894] (Figure 1a) first proved the existence of electromagnetic waves in his laboratory. His spark-based experiments [1, 2] demonstrated not only the existence of waves by showing that the transmitter in the proximity of a conducting wall generated nodes and antinodes that were compatible only with wave propagation [3], but also confirmed the theoretical prediction by James Clerk Maxwell [Edinburgh, Scotland, 1831 — Cambridge, England, 1879] that the speed of such waves was equal to the speed of light [2, 4]. On the other hand, the phenomenon remained limited to his laboratory and, even if replicated, remained confined to scientific demonstrations or little more up to 1895. It was at that point that Guglielmo Marconi [Bologna, Italy, 1874 □ Rome, Italy, 1937] (Figure 1b) managed to have his receiver buzz well over a mile away from the transmitter, and behind a hill [5, 6].