The Historic Poldhu Wireless Station
Cornwall, England

Location of the first Transatlantic radio transmission on Dec. 12, 1901
by Virginia Dahms, KD9E

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Guglielmo Marconi

At 12:30 a.m. (4:30 UTC) on December 12, 1901, in St. John's Newfoundland, Guglielmo Marconi distinguished three faint clicks through the earphones of his wireless receiver -- the Morse Code letter "S" -- and a new era was born. The signal was sent from the Poldhu Wireless Station in an austere location on a cliff along the south Cornish coast of England.

The site in Cornwall was chosen for its remoteness to keep the project out of the public eye and out of the newspapers. In 1900, Marconi decided to work in secret without the press hounding him or speculating on the outcome of his endeavor. He was only 27 years old at the time and would not be dissuaded by critics.

Concrete footing for the generator that ran the Poldhu Wireless Station erected by Marconi's Wireless Telegraph Company in 1900.
Photo by Virginia Dahms

The remains of the long-defunct Poldhu Wireless Station are visible to the intrepid seeker of Marconi lore along a stunningly beautiful, yet rugged cliff top and within age-old stone walls that surround a cow pasture.

The Poldhu Wireless Station was dismantled in 1933, four years before the death of Guglielmo Marconi.

Guglielmo Marconi was born April 25, 1874 in Bologna, Italy, the son of an Italian father and an Irish mother. His interest in scientific experimentation began as a boy and continued throughout his life.

Poldhu Wireless Station, Cornwall, 1900
From the collection of Marconi Corporation, PLC

In 1896, Marconi arrived in England, and on June 2, 1896, he took out the first patent for wireless telegraphy using radio waves. This was the start of a career that would win him the Nobel Prize in Physics in 1909.

In 1897,Marconi formed his first wireless company, The Wireless Telegraph and Signal Company. The following year, wireless telegraphy was first employed as a means of communication between ships and lighthouses.

Remnants of Marconi's transmitting station at Poldhu, Cornwall. Photo by Virginia Dahms

In March, 1898, Marconi established wireless communication across the English Channel between France and England.

In 1900, the company became Marconi's Wireless Telegraph Company. That company has grown into a global communications and information technology company which was renamed Marconi plc in 1999.

Marconi convinced investors to spend £50,000 on the transatlantic project which had no shortage of skeptics at the turn of the last century. In October, 1900, Marconi's Wireless Telegraph Company commenced building the Poldhu Wireless Station in Cornwall, England.

This array of transmitting antennas or masts at Poldhu was destroyed in storms.
From the collection of Marconi Corporation, PLC

By 1901, the Poldhu Wireless Station had successfully transmitted wireless signals to ships at distances over 200 miles.

On the other side of the Atlantic, a site on Cape Cod was originally chosen. Numerous difficulties including inclement weather necessitated the move of the receiving station from Cape Cod to St. John's Newfoundland, which was also 600 miles closer to Cornwall.

The curvature of the earth was believed to be the limiting factor as to how far radio waves could travel. Over the 1,800 miles from Poldhu to St. John's, the curvature of the earth would be analogous to crossing a mountain of water 125 miles high. Marconi's critics suggested that radio waves wouldn't make it over such distances.

Masted transmitter array toppled by Atlantic storms in September, 1901.
From the collection of Marconi Corporation, PLC

Marconi's project was fraught with difficulties. On both sides of the Atlantic, foul weather and storms destroyed transmission towers and equipment, delaying the project further and further. The first attempted transmission was on December 11, 1901, but it failed.

Due to time and financial constraints, Marconi opted not to build a masted receiving antenna array. The original receiving antenna in Newfoundland was four inches in diameter and was held aloft by a balloon which was ripped asunder in a storm. Marconi abandoned the balloon and launched another antenna on a kite tethered to an aerial wire over 550 feet long.

The transmitted power on that historic night in Poldhu, Cornwall, was about 12 kW and the wavelength 366 meters. Later observations suggested that what Marconi actually heard from the spark gap transmitter across the Atlantic was actually a harmonic.

Granite monument in Poldhu, Cornwall, England, commemorating the first transatlantic radio transmission on December 12, 1901.
Photo by Virginia Dahms

Facing overwhelming odds, Marconi and his crew accomplished what most skeptics, including scientists and business people, said couldn't be done. He proved that wireless radio communication was both possible and practical.

Despite having much of his transmitting and receiving equipment destroyed or damaged by storms just prior to his intended transatlantic transmissions, Marconi persevered and proved that despite the curvature of the earth, radio wave propagation was possible over the entire globe.

In 1902, Marconi received messages reliably over distances of 700 miles by day and over 2,000 miles by night, thus first discovering the well-known fact that radio waves propagate more effectively at night than by day.

During WWI, in 1916, Marconi attained important results in wireless telegraphy using short waves -- the 15m band. He demonstrated that short wave signals propagate efficiently by day or by night with minimum power requirement.

Commemorative plaque on the granite Marconi Monument at the top of the cliffs overlooking the sea at Poldhu, Cornwall, England. Photo by Virginia Dahms

We in amateur radio today are indebted to Marconi and his cohorts for their innovative approach, foresight, salesmanship, grueling work and tenacity to prove to the world that "wireless communication" was not only possible from a scientific and engineering standpoint, but was also commercially feasible.

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