On 30 July 2024, European navigators commemorated the 90th anniversary of Guglielmo Marconi’s first demonstration of microwave-guided navigation. In the Bay of Silence, off Sestri Levante, Italy, the historic vessel Leudo performed a blind navigation maneuver, crossing the space delimited by two buoys, guided by radio impulses transmitted from the shore. The operation was, in effect, a reenactment of radio pioneer Marconi’s demonstration of 30 July 1934.
Among participants at this year’s event was European Space Agency (ESA) Head of FutureNAV Marco Falcone, who described in a highly appreciated presentation the innovative character of Marconi’s work. Falcone traced the evolution of navigation over the past 90 years, drawing a line from Marconi to today’s GNSS systems, now capable of delivering decimeter-level precision navigation signals via satellites orbiting at 23,000 km above the Earth.
Falcone was joined by engineers and technicians, academics and other guests, all brought together by the Radio Amateurs of Sestri Levante and the Tigullio Torre Marconi Association (TTM). Some attendees watched the demonstration via live video link, with commentary by Professor Sergio Audano.
High tech history
The first demonstration of a blind navigation system was conducted by Marconi on 30 July 1934, onboard the research vessel Elettra, observed by numerous experts and representatives of Lloyd’s of London. It announced, in fact, the birth of the radio beacon, which would guide ships and planes in conditions of poor visibility for decades and would only be supplanted by modern GNSS.
An impartial English captain steered Elettra between two buoys anchored at a dis-tance of 90 meters and 800 meters from the shore, simulating the entrance to a port, with the radio beacon set up on a nearby promontory. Marconi’s beacon consisted of two parabolic reflectors with their respective horizontal illuminators, fed in phase op-position by a common transmitter, operating at a frequency of 500 MHz (wavelength of 60 cm). On the Elettra, an instrument with a moving needle indicator showed whether the vessel was proceeding to the left or right of the assigned course. The beacon also generated an acoustic signal that could be used to help keep the boat on course.
At the conclusion of the 2024 reenactment, which reconstituted all of the essential elements of Marconi’s experiment, ESA’s Falcone thanked to the Radio Amateurs of Sestri Levante and the TTM, acknowledging their exemplary radio communication and marine navigation skills. Finally, he declared, “Viva Marconi e Viva Sestri Levante,” to the great delight of the assembly.
