Aerospace and Electronic Systems Magazine March 2017 - 28

Coltano: The Forgotten Story of Marconi's Early Powerful Intercontinental Station

END NOTES
"The Coltano area is just a natural antenna", said Dale Ellenbarger, former officer in charge at the U.S. communication center
in Coltano [37]. "With mountains on three sides and the sea to
the west, it forms the shape of a bowl or a dish similar to satellite antennas. The shape of the area enables the signals to bounce
off the mountains and down to the antennas. Marconi recognized
that fact when he first built his station. The terrain features helped
him in transmitting signals to the continents of North America, Africa and Europe via radio signals. When Marconi first began his
experiments at Coltano, radio communication was in its infancy,
so it proved to be the test bed for the entire world of radio communication."

ADDENDUM: A HAWAIIAN TWIN
It is rather surprising to know that Marconi's radio station in
Coltano has a twin in the other hemisphere, at Kahuku (21.706199
N, 157.973107 W) on the North Shore of Oahu, Hawaii [40]. This
station was built in 1914 by Marconi Wireless Co., and since 1916
it provided regular radiotelegraphic services to North America
and Asia, using a 300 kW transmitter. Similarly to Marconi's radio
station in Coltano, the Kahuku's station featured a couple of large
bent antennas, each made of 12 trellises: one antenna was aimed
toward San Francisco and the other toward Japan. And, similar
to Coltano, this radio center had a sad fate. The importance of
the radiotelegraphic services provided by Kahuku's station rapidly declined after Hawaii was linked to the Mainland by undersea
cable in 1957. The station was therefore closed and the antennas
were dismantled. Today the buildings of the Marconi station in
Kahuku are vacant and in disrepair, just like the Marconi station
in Coltano.

ACKNOWLEDGMENTS

find. The preparation of this study required then a major effort to
collect, analyze, critically revise, and organize in the best possible
way such a sparse bibliographical material.
The reader interested in investigating Marconi's life and work
is referred to the following comprehensive resources: i) the archive
of the Guglielmo Marconi Foundation (FGM) [41]; ii) the MarconiCalling archive created by Marconi Corp. plc, [42]; iii) the Marconi
Archives of the Bodleian Library at the University of Oxford [2].
Concerning the latter archives, the material relating to Coltano wireless station consists of some papers, relevant to years 1902-1905,
in Shelfmark MS. Marconi 197 (32 pages), and in a photograph of
Coltano station in Shelfmark MS. Photogr. b. 63, fol. 142.
Reports of Marconi's public activities can be found in the
old issues of some Italian newspapers. In particular, the on-line
archives of Turin's newspaper "La Stampa" [43] and Bologna's
newspaper "Il Resto del Carlino" [3], [44], have proved valuable
sources of information about the history of the Coltano site.
The most comprehensive collection of Marconi's scripts was
published posthumously (in Italian) by the Italian Royal Academy,
in 1941 [45]. This anthology of Marconi's papers, speeches, and
notes is now freely available on-line. In the collection [45] there
are three papers dealing with Coltano: one is [24] and the other two
are the Italian translation of [5] and [17].
The State Archives of Pisa conserves a comprehensive collection of documents concerning the construction of the Palazzina
Marconi, including the building's drawings and blueprints, site
maps, and some correspondence about the work progress [46].

REFERENCES
[1]
[2]

[3]

The author greatly acknowledges Dr. Luigi Cobisi, General Secretary of Italradio, for his fruitful comments and suggestions, and
Prof. Umberto Mengali, Professor Emeritus from the University of
Pisa, for his patient revision of the manuscript. The author also expresses his greatest appreciation for the information provided by
Prof. Matilde Baroni and Dr. Paola Bernadini, daughters of two
former Coltano's technicians, for the passion and commitment they
provide in uncovering, spreading, and preserving the memory of
this historic site. This article is dedicated to them, to their fathers
and to all the people, from the most illustrious scientists to the
humblest laborers, who worked in Coltano and contributed to an
exciting, though unrecognized, chapter in the history of radio communications.

[4]
[5]
[6]
[7]
[8]
[9]
[10]

BIBLIOGRAPHICAL NOTES

[11]

Information about the Coltano site is rather scarce and is provided
by a multiplicity of sources which are often inaccurate from a technical and historical point of view. Also, many documents are written in Italian, have a very limited distribution, and are difficult to
28

[12]

IEEE A&E SYSTEMS MAGAZINE

Solari, L. Sui mari e sui continenti con le onde elettriche: il trionfo di
Marconi. Bocca, Milan, Italian, 1942 (in Italian).
Marconi Archives of the Bodleian Library at the University of Oxford. Catalogue available on-line: http://www.bodley.ox.ac.uk/dept/
scwmss/wmss/online/modern/marconi/marconi.html
Falciasecca, G., and Valotti, B. Guglielmo Marconi: tra storia e cronaca. Published dy Fondazione Guglielmo Marconi (FGM), Bologna,
2006 (in Italian).
Fleming, J. A. The Principles of Electric Wave Telegraphy and Telephony, 3rd ed. London: Longmans, Green & Co., 1916.
Marconi, G. Wireless telegraphic communication. Nobel Lecture,
Dec. 11, 1909.
Galligioni, G. Rilievo della conduttività del terreno in Italia, Alta Frequenza, Vol. XX, Giugno-Agosto 1951, 119-127 (in Italian).
http://www.avvocatoandreani.it/servizi/rivalutazione-monetariastorica.php
Solari, L. Storia della radio. Garzanti, Milano, Italy, 1945 (in Italian).
Vallauri, G. Il centro radiotelegrafico di Coltano. l'Elettrotecnica, Vol.
XI, N1, 2 (Jan. 5-15, 1924) (in Italian).
Silleni, S. Coefficienti di portata delle stazioni radio. Annals of Geophysics, Vol. 10, 1-2 (June 8, 1957), 145-159 (in Italian).
Pelosi, G., Selleri, S., and Valotti, B. From Poldhu to the Italian station of
Coltano: Marconi and the first years of transcontinental wireless. IEEE
Antennas and Propagation Magazine, Vol. 46, 3 (June 2004), 47-54.
Abbatangelo, G., Cavicchi, M., Manara, G., Pelosi, G., Quattrone, P.,
and Selleri, S. The early history of radiocommunications through the

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http://www.bodley.ox.ac.uk/dept/scwmss/wmss/online/modern/marconi/marconi.html http://www.bodley.ox.ac.uk/dept/scwmss/wmss/online/modern/marconi/marconi.html http://www.avvocatoandreani.it/servizi/rivalutazione-monetaria-storica.php http://www.avvocatoandreani.it/servizi/rivalutazione-monetaria-storica.php

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