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Magnificent – and Wireless


By Jan Hybertz Gøricke

Valdemar Poulsen’s arc transmitter meant great progress for wireless telegraphy, but also made wireless transmission of speech and music possible. The world-famous invention is now 100 years old.


In September 1902 inventor Valdemar Poulsen applied for a patent in respect of "procedure for generation of alternating currents with high frequency". The patent was issued on 3rd April 1903 with retrospective application.

Valdemar Poulsen’s patent describes how an arc generator – an arc transmitter – solved the problem of generating incessant high-frequency radio waves of that time, The name "arc transmitter" comes from the fact that the transmitter consists of among other things a burning carbon arc. With a spirit lamp the carbon arc was added a hydrogen-containing athmosphere which caused the frequency to increase enormously. The addition of the hydrogen-containing atmosphere is the very core of the Danish patent no. 5590.

In 1904, the first station for experiments with Poulsen’s arcs was established near Bagsvaerd Lake. The station later became the renowned Lyngby Radio. Here Valdemar Poulsen and his partner, engineer P. O. Pedersen, experimented with wireless telegraphy and telephony to a station in Esbjerg, which is why the building got its misleading name, the Esbjerg House. Parts of the Esbjerg House as well as a large collection of apparatuses have been preserved and are exhibited in Post & Tele Museum.

Poulsen’s arc transmitter never achieved commercial success in Denmark. The modest size of the country was unsuitable for wireless long-distance transmitters. Moreover, the Great Nordic Telegraph Company purchased some of the rights only to pack them away and thereby protect their expensive cable network against wireless competition. On the other hand the arc transmitter gained ground not least in the US where it transmitted wireless communication of as well private individuals as the navy.

In November 2000 members of the Danish Engineers’ Association, IDA, chose the arc transmitter as the greatest Danish engineer achievement of the 20th century. The prize was presented to a representative from the then Tele Danmark as Valdemar Poulsen was attached to KTAS from 1893.


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