Theta (SIS radio group)
Encyclopedia
"Theta" was a radio communications group that operated in Bergen, Norway during the German occupation of Norway
, communicating with the British Secret Intelligence Service
(SIS). The group was operative from December 1941 to June 1942.
Jan Dahm
, a student at the Technical school in Bergen. He had been arrested in June 1940, but was released due to a court decision 28 August 1940. The same trial saw the first death sentences for resistance work in Norway (Lund, Rendedal and Solem), but their sentences were subsequently changed to prison. Following his release, Jan Dahm was still under the Gestapo's supervision, but eventually learned to know their methods, and also built his own radio transmitter. One of Dahm's advisors on radio technology was electronics engineer Helmer Dahl
at the Chr. Michelsen Institute
. Another important contact and advisor was Major Mons Haukeland
, district leader of Milorg
.
travelled to Great Britain with the refugee ship Duen in October 1941. He returned to Bergen in November, bringing a transmitter, code and schedule. The group in Bergen had prepared a secret room in an old building at Bryggen
, which they used as headquarters. The equipment was kept at the headquarters, but brought elsewhere during transmissions. The group had regular radio contact with SIS from end of December 1941. However, there were problems, as a German radio station interfered in the traffic, pretending to represent the London Central, using the same call-sign and asking for repetitions over and over. A new crystal, with a different frequency, was brought in from London to Bergen in January, and after this the problem with the German station disappeared.
, and on 23 January 1942 "Theta" reported that the battleship Admiral von Tirpitz
, along with six destroyers and submarines had been observed in Åsenfjorden, the inner reaches of the Trondheimsfjord
. These messages prompted SIS to send Bjørn Rørholt
to Trøndelag to establish the station "Lerken", with the primary goal of reporting on the German ship movements. The "Theta" group also obtained inside information from the new submarine harbour in Laksevåg
, and they informed on the Telavåg
burning. The group cooperated with other organizations and received large amounts of information, but this was also a security problem.
agent with the cover name "Gulbrandsen", who was also a marine officer and ship's master. However, the SIS also had an agent inside the Abwehr who sent a warning to England, and "Theta" was subsequently warned. Nevertheless, group member Kristian Ottosen
was arrested on 25 June 1942, while Jan Dahm and operator Wenche Stenersen escaped to Sweden. Months later, in a massive raid at Bryggen on 17 October, the secret room was discovered, and a couple of the other group members were arrested. Jan Dahm and Bjarne Thorsen were in London at the time, ready to be sent back to Bergen to continue the group's activities, but after the October raid these plans were abandoned.
Occupation of Norway by Nazi Germany
The occupation of Norway by Nazi Germany started with the German invasion of Norway on April 9, 1940, and ended on May 8, 1945, after the capitulation of German forces in Europe. Throughout this period, Norway was continuously occupied by the Wehrmacht...
, communicating with the British Secret Intelligence Service
Secret Intelligence Service
The Secret Intelligence Service is responsible for supplying the British Government with foreign intelligence. Alongside the internal Security Service , the Government Communications Headquarters and the Defence Intelligence , it operates under the formal direction of the Joint Intelligence...
(SIS). The group was operative from December 1941 to June 1942.
Background
The "Theta" group developed among young students in Bergen. A central person was the amateur radio operatorAmateur radio operator
An amateur radio operator is an individual who typically uses equipment at an amateur radio station to engage in two-way personal communications with other similar individuals on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted an amateur radio...
Jan Dahm
Jan Dahm
Jan Dahm was a Norwegian resistance member during World War II. He was among the first group of people to be subject to court-martial during the German occupation of Norway, and later initiated and headed the Secret Intelligence Service group Theta, which operated in Bergen from December 1941 to...
, a student at the Technical school in Bergen. He had been arrested in June 1940, but was released due to a court decision 28 August 1940. The same trial saw the first death sentences for resistance work in Norway (Lund, Rendedal and Solem), but their sentences were subsequently changed to prison. Following his release, Jan Dahm was still under the Gestapo's supervision, but eventually learned to know their methods, and also built his own radio transmitter. One of Dahm's advisors on radio technology was electronics engineer Helmer Dahl
Helmer Dahl
Helmer Hartmann Dahl was a Norwegian engineer.He graduated as an engineer from the Norwegian Institute of Technology in 1931, and was hired at the Chr. Michelsen Institute in 1935. From 1942 to 1945 he was in exile in the United Kingdom...
at the Chr. Michelsen Institute
Chr. Michelsen Institute
The Chr. Michelsen Institute was founded in 1930, and is currently the largest centre for development research in Scandinavia. CMI is an independent, non-profit research foundation for policy-oriented and applied development research. Headed by the director Ottar Mæstad, it employs 40 social...
. Another important contact and advisor was Major Mons Haukeland
Mons Haukeland
Mons Olai Haukeland was a Norwegian gymnastics teacher and military officer, and district leader of Milorg during World War II until his arrest in 1943. He was imprisoned at Grini concentration camp from 8 to 9 December 1943, then at Sachsenhausen until the camp was liberated...
, district leader of Milorg
Milorg
Milorg was the main Norwegian resistance movement in World War II....
.
Contact with SIS
The group was already in possession of radio equipment and expertise. In order to establish contact with London, high school student Bjarne ThorsenBjarne Thorsen
Bjarne Winter Thorsen was a Norwegian resistance member during World War II and later a naval officer.-World War II:...
travelled to Great Britain with the refugee ship Duen in October 1941. He returned to Bergen in November, bringing a transmitter, code and schedule. The group in Bergen had prepared a secret room in an old building at Bryggen
Bryggen
Bryggen , also known as Tyskebryggen is a series of Hanseatic commercial buildings lining the eastern side of the fjord coming into Bergen, Norway. Bryggen has since 1979 been on the UNESCO list for World Cultural Heritage sites. The name has the same origin as the Flemish city of Brugge.The city...
, which they used as headquarters. The equipment was kept at the headquarters, but brought elsewhere during transmissions. The group had regular radio contact with SIS from end of December 1941. However, there were problems, as a German radio station interfered in the traffic, pretending to represent the London Central, using the same call-sign and asking for repetitions over and over. A new crystal, with a different frequency, was brought in from London to Bergen in January, and after this the problem with the German station disappeared.
Reports
The "Theta" group acquired information from several sources. A telegram sent 16 January reported on a large ship with destroyers sailing into the TrondheimsfjordTrondheimsfjord
The Trondheimsfjord , an inlet of the Norwegian Sea, is Norway's third longest fjord at long. It is located in the west central part of the country, and it stretches from Ørland in west to Steinkjer in north, passing the city of Trondheim on its way...
, and on 23 January 1942 "Theta" reported that the battleship Admiral von Tirpitz
German battleship Tirpitz
Tirpitz was the second of two s built for the German Kriegsmarine during World War II. Named after Grand Admiral Alfred von Tirpitz, the architect of the Imperial Navy, the ship was laid down at the Kriegsmarinewerft in Wilhelmshaven in November 1936 and launched two and a half years later in April...
, along with six destroyers and submarines had been observed in Åsenfjorden, the inner reaches of the Trondheimsfjord
Trondheimsfjord
The Trondheimsfjord , an inlet of the Norwegian Sea, is Norway's third longest fjord at long. It is located in the west central part of the country, and it stretches from Ørland in west to Steinkjer in north, passing the city of Trondheim on its way...
. These messages prompted SIS to send Bjørn Rørholt
Bjørn Rørholt
Bjørn Arnold Rørholt was a Norwegian engineer, military officer, Secret Intelligence Service agent and resistance member during World War II.-Early life:...
to Trøndelag to establish the station "Lerken", with the primary goal of reporting on the German ship movements. The "Theta" group also obtained inside information from the new submarine harbour in Laksevåg
Laksevåg
Laksevåg is a borough of the city of Bergen, Norway.-Location:Laksevåg was separated from Askøy as a municipality of its own July 1, 1918. It was merged with Bergen January 1, 1972....
, and they informed on the Telavåg
Telavåg
Telavåg is a small village in the municipality of Sund, located 39 km south west of Bergen, Norway, with a population of about 600.-Telavåg tragedy:...
burning. The group cooperated with other organizations and received large amounts of information, but this was also a security problem.
End of operation
During spring 1942 the group received information that turned out to be misleading or wrong. This misinformation was later tracked to one particular source, an AbwehrAbwehr
The Abwehr was a German military intelligence organisation from 1921 to 1944. The term Abwehr was used as a concession to Allied demands that Germany's post-World War I intelligence activities be for "defensive" purposes only...
agent with the cover name "Gulbrandsen", who was also a marine officer and ship's master. However, the SIS also had an agent inside the Abwehr who sent a warning to England, and "Theta" was subsequently warned. Nevertheless, group member Kristian Ottosen
Kristian Ottosen
Kristian Ottosen was a Norwegian non-fiction writer and public servant.While still a student, he was also active in the Norwegian resistance movement during World War II and was imprisoned as a Nacht und Nebel inmate...
was arrested on 25 June 1942, while Jan Dahm and operator Wenche Stenersen escaped to Sweden. Months later, in a massive raid at Bryggen on 17 October, the secret room was discovered, and a couple of the other group members were arrested. Jan Dahm and Bjarne Thorsen were in London at the time, ready to be sent back to Bergen to continue the group's activities, but after the October raid these plans were abandoned.