1901 - Wireless Telegraphy

Project Overview
1800s - Land Telegraphy
1874 - Guglielmo Marconi - a Tribute
1895 - Wireless Telegraphy
1901 - Wireless Telegraphy
1902 - Wireless Telegraphy in Australia
1904 - Australian Coastal Radio
1906 - Wireless Telephony
1912 - Melbourne Radio - VIM
1914 - Shortwave Wireless Telephony
1920s - Commercial Shortwave Telephony Development
1920s - Receivers
1920 - The huge RCA Longwave Station in New York
1920 - Wireless broadcasting in Australia
1920s - First shortwave stations in Victoria
1921 - Discovery of Shortwave Propagation
1921 - Koo Wee Rup (Victoria) Experimental Wireless Receiving Station
1923- Longwave Broadcasting in Australia
1923 - Evolution of Australian Domestic Radio
1924 - 3LO - Melbourne's Second Broadcaster
1924 - 3AR - Melbourne's first broadcaster
1924 - The Braybrook (Melbourne) Transmitting Site
1925 - First Shortwave Stations in Western Australia
1926 - First Shortwave Stations in New South Wales
1926 - RAAF Communications - Laverton (Vic)
1927 - Beam Wireless Worldwide
1927 - Beam Wireless from Australia
1928 - ABC Lyndhurst (Victoria)
1930 - AWA Receiving Station at La Perouse (Sydney)
1930 - AWA Radio Centre at Pennant Hills
1933 (to 1969) - Shortwave Radio Clubs in Australia
1936 - Ship Broadcaster - the MS Kanimbla
1939 - Belconnen Communications Station (Canberra)
1940 - RAAF Receiving Station at Werribee (Victoria)
1941 - RAAF Frognall (Melbourne)
1941 - ABC Brisbane
1942 - Army Wireless Chain - west of Melbourne
1942 - Dutch Stations in Australia
1943 - ABC Radio Australia - Shepparton (Victoria)
1943 - Army Shortwave HF Stations in Melbourne
1944 - ABC - Radio Australia - Looking Back
1945 - PMG Receiving Station - Highpark (Victoria)
1945 - Radio Australia - DXers Calling
1946 - Radio Australia - Communications Programs
1946 - VNG Time Signal Station
1948 - Radio Australia QSL Cards
1948 - ABC Sydney
1966 - ABC Cox Peninsula (Darwin)
1970 (to 2012) - Shortwave Radio Clubs in Australia
1975 - ABC Gnangara (Western Australia)
1975 - ABC Carnarvon (Western Australia)
1978 - Omega Navigation Station - Woodside (Victoria)
1985 - ABC Northern Territory
1989 - ABC Brandon (Queensland)
2003 - Private Shortwave Broadcasters
Timeline - Part One - 1839 to 1927
Timeline - Part Two - 1928 to 2012
SPECIAL - Licencing of Shortwave Broadcasters
SPECIAL - Radio Receivers for Shortwave
SPECIAL - Radio Monitoring as a Hobby
Bibliography, References and Resources
Links to the author's personal websites

1901 - Marconi's transmitter

Marconi's Historical Message
December 12, 1901, the first of Marconi’s dreams came true, when his historic message – the letter “S” was sent in Morse from Poldhu, in Cornwall, England, over a trans-Atlantic path of about 3000 km to St John's, Newfoundland, using a spark transmitter.

This prearranged transmission was received by Marconi with a receiver connected to a 100 metre long antenna trailed from a kite.

Perhaps we could have a closer look at what Marconi was trying to achieve in those opening days of the 20th century, and we examine in some detail how he came to make that historic message.

Marconi believed that his first endeavours to prove that wireless signals could be transmitted, and received, over long distances, should relate to the trans-Atlantic path, and for that purpose a transmitting station, at the time the most powerful ever built, was constructed at Poldhu, Cornwall, England.

The antenna system consisted of a ring of 20 masts, each about 70 metres high. Another similar station was erected in Cape Cod, Massachusetts. However, at the end of August 1901, when the antenna construction at Poldhu was nearly complete, a storm there virtually destroyed what had already been accomplished, and the entire facility was wrecked.

Nevertheless, Marconi organized a substitute emergency antenna, a simpler device consisting of 60 vertical wires, 60 metres high, connected to a stay stretched between t two masts 60 metres high.

In November 1901, he sailed from Liverpool, accompanied by his assistants, and reached St. Johns on December 6.

Bad weather hampered Marconi’s experiments in attempting to set up a suitable receiving system, but he did manage to put up a kite carrying an antenna wire of about 100 metres long. Suddenly, at about 12.30 pm, he heard a succession of three faint clicks on his telephone receiver, corresponding to the three Morse dots of the letter S. This occurred several times, removing all possibility of doubt that trans-Atlantic transmission had been achieved. He repeated the experiment on the following day – successfully.

We should note that Marconi's equipment was extremely crude compared with present day standards – tubes and transistors had not been invented – amplifiers did not exist – no facilities existed for generating continuous waves. All that was available was equipment for transmitting damped waves by means of irregular spark discharges.

In 1901, Marconi started to set up a network of permanent wireless stations, specifically for maritime communications, following the establishment of the Marconi International Marine Company in 1900.

His company built stations on the British and Irish coasts, in Belgium, Germany and in the USA.

By the end of 1901, the British and Italian Navies had adopted Marconi's invention, and radio telegraphy facilities had been installed in British and foreign merchant ships, and the Cunard liners Luciana and Compania.

In 1903, about 12 months after Marconi's historic message, two-way contact was established across the Atlantic.

1901 - Marconi Spark Gap Transmitter

1910 - Navy Spark Gap Transmitter

Early Spark Gap Transmitters
The value of wireless communications was highlighted in 1909 when the White Sitar liner Republic collided off the American coast with the Italian SS Florida. The number of lives lost in the tragic 1912 Titanic disaster would have been far worse if it had not been for the existence of radio telegraphy, and the dedication and bravery of the Marconi Marine radio officers between the Poldhu station, and one that had been built at Cape Breton, in Canada.

See the Website of the Cape Breton Wireless Heritage Society for comprehensive information.

In the early 1900s, receiving equipment was extremely simple, consisting essentially of the coherer detector, or the magnetic detector developed by Rutherford and Marconi, together with a variety of other forms of detector which had been invented.

In 1903, a Dutch engineer, Valdemar Poulson, succeeded in modifying the “singing arc" of the London engineer, Duddel, in such a way as to produce a means of powerful and continually sustained oscillations of several hundred thousand per second.

The Poulson Arc form of transmitter quickly rose in popularity, until in 1925 there were nearly 80 stations worldwide, equipped with transmitters of this type with 25 HP or more. There was rapid advancement in Germany and the USA, in the design and construction of alternating current dynamo machines which could generate oscillating currents of sufficient speed to serve electromagnetic propagation.

This new technology was known as the “high frequency alternator”, and enabled a continuous wave (CW) to be produced, and the famous stations at Nauen (Germany) and at Long Island (New York) were equipped in this way.

Dr Ernest Alexanderson (1878-1975) was the American engineer who was responsible for the development of the HF alternator and at the peak of its advancement, by 1919, output powers of 200 kW were achieved, at frequencies of up to 100 kHz.

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