Faraday, Maxwell, Hertz: The Birth of Radio Waves

On October 29, 1831, Michael Faraday, an English physicist, made a groundbreaking discovery: electricity could be transmitted without wires. This revelation predated the introduction of the electric light bulb by 50 years.

Faraday's insights are still echoed today. When questioned by William Gladstone, the British Finance Minister, about electricity's practical applications, Faraday famously remarked, "One day, sir, you may tax it." His discovery laid the groundwork for what would become a significant phenomenon. In fact, the government now taxes these advancements, much like what Faraday anticipated.

During this period, physicists endeavored to formalize Faraday's findings. In 1864, Scottish physicist James Clerk Maxwell articulated the elegant laws of physics known as Maxwell's equations, which provided a profound explanation of Faraday's work.

Maxwell's equations foretold the existence of a phenomenon known as electromagnetic waves.

No, this was not mere speculation.

Electromagnetic waves are a universal phenomenon, omnipresent in our environment, and can even be perceived visually. Yet, Maxwell, along with Albert Einstein, were among the first to grasp that light is a type of electromagnetic wave.

Maxwell's prophecy indicated the presence of invisible light, commonly referred to as radio waves. These waves represent more than the limited reach of electricity Faraday had initially discovered.

In 1886, amidst global experiments validating Maxwell's equations, German physicist Heinrich Rudolf Hertz made a revolutionary advancement: the dipole antenna, still in use today. This antenna directly captures the electromagnetic waves that traverse the air.

Dipole antennas operate on the principle that the invisible electric field produced by electromagnetic waves accelerates electrons within a wire. This was a monumental breakthrough. However, Hertz concluded his research with a rather dismissive note:

> "It’s of no use whatsoever… this is just an experiment that proves Maestro Maxwell was right — we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there."

When asked about the practical implications of his findings, Hertz replied:

> "Nothing, I guess."

In hindsight, perhaps Hertz failed to recognize the potential of his discovery. Nevertheless, radio waves are also known as Hertzian waves, and the frequency unit Hertz (Hz) bears his name.

From Hertz to Marconi: The Evolution of Radio

The University of Bologna, Italy, hailed as the world's oldest university, was founded in 1088. Its notable alumni include Copernicus, Albrecht Dürer, and the poet Dante.

Guglielmo Marconi, the central figure in this tale, also attended the University of Bologna.

Born in 1874 in Bologna, Italy, Guglielmo was the second son of Giuseppe Marconi and Annie Jameson, an Irish woman from County Wexford. Their romance blossomed during a trip to Italy, reminiscent of a cinematic tale. Annie frequently visited her sisters in Tuscany, possibly leading to their romantic encounter.

However, their story includes twists beyond a simple film narrative.

Annie spent every summer in Tuscany with her son Guglielmo, where she hired a tutor named Vincenzo Rosa. At 17, Guglielmo was introduced to Hertz’s discoveries. Rosa not only educated him about the newly uncovered Hertzian waves but also engaged him in hands-on experiments. Guglielmo became so captivated by these waves that he enrolled at the University of Bologna to study electromagnetism at 18.

Author’s note: I have visited the University of Bologna, where Guglielmo studied, numerous times. Bologna is renowned as Italy's culinary capital, brimming with delectable dishes. On one occasion, I promised a woman I met there to dine together, only to discover my favorite restaurant was unexpectedly closed. After pleading with the annoyed owner, he graciously agreed to open for me, saying, "Today is your special day! Okay, I’ll open in an hour!" Bologna is a charming city. (Smile.)

Guglielmo created numerous prototypes for wireless transmitters and receivers, showcasing nearly completed devices to his mother in 1894.

The following year, he uncovered techniques still recognized today, such as elevating the antenna and grounding one end, successfully extending transmission distance to two miles (3.2 kilometers).

Guglielmo approached Maggiorino Ferraris, the Italian Minister of Post and Telegraphs, seeking a research grant but received no response.

Disheartened by Italy's lack of support, he and his mother Annie relocated to London at the age of 21. There, Guglielmo patented his wireless device and conducted public demonstrations to attract funding.

His mother’s family, the Jameson Distillery, which had weathered the Temperance movement in Ireland, had influential connections. Sir William Henry Preece, a British Post Office engineer who had studied electromagnetism under Faraday, became a significant ally.

In 1897, Guglielmo finally achieved wireless communication across the sea. By 1900, the Japanese Navy was developing a radio system, with a Japanese transmitter ready for the Russo-Japanese War.

Transatlantic Communication and Marriage

In December 1901, Guglielmo undertook the first test to determine if radio communication could cross the Atlantic. At the time, many believed that radio waves could not travel beyond the horizon due to the earth's curvature. However, Guglielmo succeeded in transatlantic communication. The article The Man Who Manipulates Lightning in Science for Adults (Japanese) vividly recounts the scene:

> "At noon on the 12th [December 1901], Marconi held the telephone receiver to his ear. He had developed a device to record the signals received by radio communication, but considering the possibility of weak signals, he opted to listen himself. The transmitter was set to send the Morse code signal for "S" at 11:30 a.m. St. John’s time."

Marconi was desperately trying to find the transmitter’s wavelength with one hand free. The wind was so strong that he struggled to confirm the signal. After a moment, he took a sip of hot cocoa with a splash of scotch, regained his focus, and concentrated intently.

He picked up the receiver again, listening intently. Then, he heard it: the signal, three dots in Morse code. The next day, this moment reverberated worldwide.

What a captivating tale! Guglielmo’s “hot cocoa with scotch” was likely Irish whiskey.

However, this narrative may be exaggerated. The experiment's success is debated due to the lack of documentation and the challenging conditions under which it was conducted. Nevertheless, Guglielmo continued to innovate and eventually commercialized transatlantic communication, outpacing his rival, Nikola Tesla.

Guglielmo maintained strong ties to Ireland, marrying Beatrice O’Brien in 1905. She was the daughter of Edward O’Brien, 14th Baron Inchiquin, an Irish noble.

In 1909, after four years of marriage, Guglielmo was awarded the Nobel Prize in Physics, sharing the honor with German physicist Karl Ferdinand Braun for their contributions to wireless communication. By modern standards, Maxwell, Hertz, and Faraday would have deserved recognition first, but given that the Nobel Prize was initiated in 1901, Marconi was indeed fortunate.

The Marconi Company, founded by Guglielmo, sent radio operators to ships navigating the Atlantic. Notably, the distress signal from the Titanic, which sank on April 15, 1912, was transmitted by two Marconi operators, one of whom narrowly escaped and later met Guglielmo in New York.

The Applications of Electromagnetic Waves

Guglielmo Marconi’s creation of radio communication paved the way for radio broadcasting, revolutionizing global communication. The first entertainment broadcast in England, initiated by Marconi, set the stage for what would become the BBC.

When it was discovered that metals could reflect electromagnetic waves, radar technology emerged. Radar enables the detection of aircraft from afar by sending out electromagnetic waves and capturing their reflections. It played a crucial role in the Allied victory during World War II. Japan was the first nation to develop the necessary antenna technology for radar, later selling the patent to the Marconi Company in 1926.

The advancement of radar subsequently led to the creation of the microwave oven, an efficient electromagnetic wave generator that heats food by targeting water molecules.

Electromagnetic waves have diverse applications. For instance, have you ever had your liquids checked at an airport? All airports in Japan utilize devices that determine whether the contents of a plastic bottle are water or flammable substances. These devices assess the contents by emitting electromagnetic waves between visible light and radio waves. According to the developer's scientific paper, the device can also differentiate between soft drinks and alcoholic beverages.

The next time I board a plane, I’ll honor Guglielmo Marconi by bringing along a plastic bottle of Jameson whiskey from the distillery owned by his mother Annie’s family.

One Last Note

Thank you for indulging in this story. You might also appreciate this fascinating TED talk on Nikola Tesla.