[HCDX] The Grimeton Radio Station: a Unique Piece of IT History

["Mike Terry" <miketerry73@xxxxxxxxxxxxxx>]

By Hans Bengtsson
Epoch Times
May 17, 2005

Grimeton, Sweden - The methods we use to communicate with each other are
under constant development, and technology offers ever more sophisticated
means of human contact.

By looking back, we can get an idea about where this progress will lead us
in the future. In Grimeton, just outside Varberg on the Swedish west coast
stands a piece of IT-history of world interest.

Six steel towers, 127 meters high, are visible from a great distance in the
level landscape. Despite their impressive size, the towers are not what´s
important. They are simply supporting the eight antenna wires, almost
invisible from the ground. These wires kept up the connection with the USA,
when the ultra-longwave transmitter was in use during the 1920´s and 1930´s.
It is now on the UNESCO World Heritage List.

The poles are strategically located, with nothing but the open sea in front
of them, all the way to New York. The site was carefully selected when the
Swedish government and parliament decided to modernize communications in the
early 1920´s.

Experience from World War I, in which sabotage of international cable
communications had made clear the increasing need for wireless
communication, less vulnerable to third party interference. However,
wireless communication wasn't completely new when the transmitter in
Grimeton was built. The Italian engineer Marconi had developed radio
telegraphy in the late 19th century (see adjacent article).

In Karlsborg in the south of Sweden, a transmitter based on earlier "spark"
technology was available for Morse code communication with other countries.
It wasn't powerful enough for transatlantic communication, however, and its
technology had become outdated.

The transmitter installed at Grimeton was state of the art in 1924. A 200
kilowatt AC generator would generate the signal, which, provided with the
right kind of auxiliary equipment, was capable of transmitting both speech
and music. This was not its purpose however. It was used strictly for
telegraphic communication.

Originally there were two alternators in Grimeton. Now one of them is left
and it is the only still functioning Alexandersson alternator in the world.

The transmitter was built in the USA by General Electric. It was designed by
Swedish immigrant Ernst Alexandersson, born in 1878. The new innovation was
its AC generator which, unlike earlier DC models, generated a carrier wave
which was constantly on the air. Apart from Morse code signals, speech as
well as music could be modulated with this carrier wave. A first prototype
was completed in 1906, and on Christmas Eve that year, the first
transmission was made. People out at sea and others in possession of
telegraphic receivers, were then surprised by speech and singing. The first
audio radio transmission in Swedish was a Christmas gift for them.

The radio transmitter at Grimeton was part of a global radio link system for
telegraphy which, by the early 20´s, included 18 stations. It uses
ultra-long-wave, with a wavelength of just over 18 kilometers for the first
years, later to be reduced to just over 17 kilometers. The two Alexandersson
generators at Grimeton were online by 1924.

Today, one remains. It is the only surviving, still functional,
Alexandersson generator in the world.

The Swedish government granted 4 million Swedish crowns towards the building
of the station, and construction began in 1923. The first transmission from
Grimeton was carried out during the night of the last of November in 1924.
July the following year, the station was officially opened by the Swedish
king Gustaf V, by sending a telegram to the president of the United States
Calvin Coolidge, in which he praised the transmitter and the "democratic
rule, under which, millions of Swedes have found a home."

Harald Lövhede and Bo Johansson are members of the Alexander society, named
after the designer. The society is responsible for taking care of the World
Heritage in Grimeton. They provide guided tours of the station, which was
online more or less around the clock during the 20´s and 30´s.

Bringing the machine online was an involved procedure, taking some 10 to 15
minutes. Bo Johansson shows some of the many tasks performed at startup, and
plays back a recording of the procedure, taking you back in time. You can
hear the power getting switched on, cooling pumps starting up and the big,
heavy generator wheel slowly accelerating, all amidst a deafening noise. The
machine is brought online regularly even nowadays, for maintenance, to
grease the ball bearings. It´s been done several times this year already,
says Harald Lövhede.

At the operator table, a few meters away from the noisy generator, the
station manager would sit and tap out the signals, using the Morse key. Bo
Johansson says that there´s not much difference between the Morse signals
this station used to transmit and todays computerized communication. Both
use "ones and zeros" or "information- non-information." Grimeton was capable
of sending a hundred five-letter words a minute, but in actual use never
sent more than fifty.

Nowadays, modern technology has taken over at Grimeton. In 1939, shortwave
transmitters took over most of the telegram traffic. In the 60´s, the
Alexandersson generator was replaced by another ultra-longwave transmitter,
still in use today for submarine communications. Only the really long
frequencies can reach deep into the ground and water.

This is the reason why it´s been possible to preserve the transmitter for
coming generations. The Swedish navy has had a deal with the Grimeton
station for many years, the proceeds from which has made the preservation of
the
transmitter possible.

http://www.theepochtimes.com/news/5-5-17/28849.html



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