The Lidingö trials
Terrestrial mobile systems were established in many major cities all around the world after the war, using one-way communication radios.
In Sweden, the number of vehicles with terrestrial mobile communication radios rose during the 1950s to about 9,000, with local or restricted systems for the police, taxis, trucking companies and others. In each individual case, a permit had to be granted by Televerket’s special department for planning, standards and approval of what were called local information services.
Swedish telephone and radio engineers were greatly interested in the mobile phone networks emerging in the US. The Telegraph Board (which changed its name to Televerket in connection with its centenary on November 1, 1953) was also eventually to play a pioneering role in mobile telephony.
One of those who was particularly interested was Håkan Sterky, professor of telegraphy and telephony at the Royal Institute of Technology, and later also its president, who was appointed in 1942 to be director-general of the Telegraph Board. A few years after the war, he assigned Ragnar Berglund, a graduate engineer in the board’s radio division, and Sture Lauhrén from its engineering division to study the possibilities of an automatic carphone system.
In a system like this, it was necessary for a vehicle to be identified by the base station and addressed selectively. This would preferably be arranged using individual numbers that could be exchanged between the vehicle and the base station without the caller having to act. The network now being planned was allocated four radio channels, the frequencies, as in the US, in the 160 MHz band.
Late in the autumn of 1950, Berglund and Lauhrén installed a pilot system in Lidingö, a Stockholm suburb. This location was chosen because its 90-meter water tower offered a good position for the base station.
On Monday, December 3, 1950, Lauhrén drove the Telegraph Board’s specially equipped car slowly along Vasavägen in Lidingö. He dialed the number 23 90 00, the speaking clock. Through the static he could make out the familiar sound of its voice. The system worked.
He then drove around in Stockholm with his wife, Disa, even though it was strictly forbidden for private passengers to travel in the board’s official vehicles. They phoned everyone they knew. “It was so exciting I just couldn’t help it,” Sture Lauhrén admitted to a newspaper much later.
Disa Lauhrén’s parents did not know what to think when their daughter and son-in-law came driving up to their house in Sollentuna, just outside Stockholm. “We could see my parents standing in the window while we were still talking to them on the carphone. ‘Can you see us driving through the gate now?’ we asked, but they would not believe their own eyes. ‘The girl has lost her mind,’ I heard them saying to each other,” Disa recalled. “Everyone reacted in the same way and thought it was all very strange.”
As a result of these trials, the Telegraph Board started planning two fully automatic carphone systems, one for Stockholm and one for Gothenburg.
Author: Svenolof Karlsson & Anders Lugn
The mobile phone equipment used in the first successful trials on Lidingö
Håkan Sterky with an Ericofon and older models.
Håkan Sterky, Telegrafverket’s director-general, testing different types of old telephones
Different types of old telephones