History: Measurement Building / TNO on the Plains of Waalsdorp


The history of TNO on the Plains of Waalsdorp


Pre-World War II years: The establishment of the Measurement Building and the first research

In 1924, reports in foreign and Dutch newspapers appeared about ‘deadly rays’. These and other mysterious rays would have been observed especially in Germany. Ignition mechanisms were disrupted, planes crashed for inexplicable reasons and cars halted. [These messages were probably based on the hoax by the English researcher Harry Grindell Matthews]. As a result of these reports, questions were asked in a secret meeting of the Defence Commission of the House of Representatives to the Minister of War. The minister, Dr. J.J.C. van Dijk, promised to investigate the reports and asked for advice from Prof. Dr. Hendrik Antoon Lorenz.
As a result of the conversation with Lorenz, by order Secret Litt. R.108 dated November 25, 1924, the Minister of War established the Commission for Physical Capabilities, with the task “to study the case of physical capabilities (…) to its full extent and to indicate globally the direction in which in the field of physics and related sciences must be searched for – solutions that are applicable for our purposes – for each part of that case, and to advise him, Minister of War, on matters pertaining to that question.” Prof. jhr. Dr. Elias was invited to chair the Commission. Members of the Commission were experienced officers stemming from various parts of the Armed Forces, and representatives from various scientific disciplines. Soon thereafter, Elias discovered that the rumours about the deadly rays could not be based on reality.

Prof. Jhr. Dr. G.J. Elias
Prof. jhr. dr. G.J. Elias

It took until 1934 before the deadly ray discussion became news in the United Kingdom (see: Brian Johnson, The Secret War). 

The mandate of the Minister to the Commission went beyond the “deadly rays”; it was the assignment to apply physical principles to military equipment to improve their performance and to advise the Minister based on research. The Commission felt it necessary to make housing available where research could be carried out under the guidance of the young scientist Ir. J.L. van Soest was appointed on 25 February 1927. The search for a militarily suitable place for experiments was linked after a while to the decision to build a new building for the Military Weather Service on the Plain of Waalsdorp (in Dutch: Vlakte van Waalsdorp/Waalsdorpervlakte; (see: Geology and archaeology of the Vlakte van Waalsdorp) near the current TNO building. On December 1, 1927, the Meetgebouw (“Measurements Building”) started its operations with Ir. van Soest and his assistant instrument maker P.D. Groot. This date has since been celebrated annually as the day of the foundation of the laboratory. In order not to create unnecessary suspicion in the pre-war years, the building was given the obfuscating name Meetgebouw instead of “laboratory”. The name Meetgebouw was in use until the German invasion in 1940. In the Meetgebouw three rooms were available with a total floor area of 130 m2.

Ir. J.L. van Soest
Ir. J.L. van Soest


The Measurement Building in 1927 - painting by G. Mooij after an original photograph
The Measurement Building in 1927 – painting by G. Mooij using an old photo


Kamp Waalsdorp met het Meetgebouw - foto Koninklijke Luchtmacht (1930)
The military barracks ‘Kamp Waalsdorp’ with the Measurement Building (photo courtesy Royal Netherlands Air Force (1930))

At the end of 1936, the Ministry of the Interior notes that the frequency band 75-81 MHz (4,000-3,750 m), originally reserved for the “deadly beam and killing engines”, is now less needed and “can be given away as needed” (although a certain band in this frequency band would be useful for future military purposes).


Experimental listening device
Experimental listening device

Van Soest began researching acoustic listening devices for aircraft detection and interception (see: Technical topic Air Acoustics) in use by the Royal Netherlands Army. He developed a Dutch listening device because the industrial devices showed insoluble defects. The successful development of the “Van Soest” listening device ultimately led to production in the industry and commissioning by the Royal Netherlands Army.

In 1937, the Minister of War decided that, because of its secret character, the work of the Commission for Physical Capabilities would not come to fall under the competence of the in 1932 established by law Organisation for Applied Scientific Research (TNO).

Subsequent projects were the development of a meteorograph for the Military Weather Service, and the development of infrared equipment for detecting possible hostile ships crossing a river. Projects led by jhr. ir. J.L.W.C. von Weiler, who joined the “Measurement Building” in 1934, included the development of an advanced radio transceiver for the Artillery (see: Technical topic Radio communication), the acoustic listening device for aircraft observation, and the development of the ‘electrical listening device‘ (‘radar’). The topics IFF (Identification Friend or Foe), detection of landmines and underwater acoustics were still in the experimental phase.

The number of employees of the Meetgebouw grew in the pre-war years to 37 in 1940. The floor space increased to 788 m2 in 1940.

During the invasion of the Germans in May 1940, two ‘electric listening devices’ were in operation, one of which was operated on the Malieveld in The Hague. On May 15, a wooden barrack on the Waalsdorpervlakte in which all secret equipment was collected was deliberately set on fire so that the equipment would not fall into German hands. Just before the capitulation of the Netherlands, Von Weiler and Staal escaped to England taking with them the documentation of the electrical listening device. In England, he worked with English scientists on the further development of radar until 1946.

Jhr. ir. J.L.W.C. von Weiler
Jhr. ir. J.L.W.C. von Weiler


German Occupation 1940 – 1945

In 1941, the Meetgebouw with over twenty staff members was included in the PTT organisation as the Physics Laboratory. In 1943, the Meetgebouw employees moved house to the Central Workshop of the PTT on the Binckhorstlaan because the Waalsdorpervlakte became ‘Sperrgebiet’. During the war period attempts were made to avoid work for the occupying forces, which partially succeeded (see personal story). Clandestine work was carried out on a broadcasting station that came into operation as Herrijzend Nederland 3 on wavelength 301.5 metres on May 18, 1945. The transmitter was operated by laboratory staff. Messages of powerful reception and quality came from all over the Netherlands. The station transmissions were also received in Hamburg, south of Paris and in southern England. After the Lopik transmitter came back into operation, the transmitter was changed and worked at 245 m as Hilversum – Herrijzend Nederland until September 4, 1945. The transmitter was then moved and operated as an auxiliary transmitter of the P.T.T. in Beek, Limburg.

After the war

On December 15, 1945, the Physics Laboratory transferred back from the P.T.T. to the Ministry of War. In 1946, the ‘normal work’ was picked up again. The Physics Laboratory remained housed at the P.T.T. until 1 December 1947. Amongst other research topics, the laboratory worked on infrared applications needed by the army in the East Indies.
On July 12, 1947, the Rijks Verdedigings Organisatie (RVO) – ‘National Defence Organisation’-  was established. The Physics Laboratory (PhL) was incorporated into the Netherlands Organisation for Applied Scientific Research (TNO)’s RVO. The laboratory returned to the Vlakte van Waalsdorp where the pre-war activities in areas such as radio, radar, and infrared technology were restarted. Internationally, the war had led to a wide range of (military) technological developments. To catch up on the lost years and to acquire an international position in the field of defence research, the PhL explored new areas of research such as passive and active sonar technology, phased array radar technologies, electronic calculation methods, and operational research. In the 1960s, the laboratory had a global leading role in the field of digital fire control and assisted the United States with this technology. Due to the strong growth in personnel, a stone building was added which was later expanded with more barracks.

In 1969, a completely new building (viewed from above in the form of an eight) was built at the edge of the Waalsdorpervlakte including an atomic bomb shelter given the Cold War era. The story about the artworks in the entrance halls of TNO and NATO STC and the thread sculpture is an interesting story to read. Mid of the 1980s, the Physics Laboratory comprised the following research groups: Physics, Far Infrared, Telecommunication, Microwaves, Information Processing Systems, Signal Processing, (underwater) Acoustics, Mine countermeasures and Operational Research. These research groups were supported by the Electronics group, Computer group, workshops and administration.

Physics Laboratory TNO (1965) - painting by G. Mooij
Physics Laboratory TNO (1965) – painting by G. Mooij


The new building in 1969
The new building in 1969

LEOK at Oegstgeest

After his return to the Netherlands in 1946, jhr. ir. J.L.W.C. von Weiler, who was incorporated into the Royal Netherlands Navy during his stay in England, continued his radar development and consultancy work as Head of the Development and Test Division of the Navy Radio Service, Oegstgeest, Netherlands. In 1950, this department consisted of 25 persons and became the Laboratory for Electronic Developments (LEO). LEO was aimed at filling the immediate needs of the Royal Netherlands Navy with operational equipment for radio communication and radar. In 1955, the LEO activities were extended with activities for both the Royal Netherlands Army and the Royal Netherlands Air Force. For that reason, the laboratory name was changed to the Laboratory for Electronic Developments for the Armed Forces (LEOK). The LEO (and later LEOK) shared a building with the Navy Electronic Optical Works (MEOB) in Oegstgeest.

The LEOK and the MEOB, Oegstgeest
The LEOK and the MEOB, Oegstgeest


First floor of the MEB building in use by the Test and Development Department, later LEO and LEOK
The first floor of the MEB building is being used by the Test and Development Department, which became the LEO and later the LEOK

In 1958, the LEOK moved into a new two-story building, which created space for research in the field of radar systems, training and simulation equipment.

LEOK building in use between 1958-1984
LEOK building in use between 1958-1984

In 1977, the number of employees of the LEOK had grown to 150 under the management of director F. van Hutten. In the same year, the armed forces decided to abandon the military status of the LEOK by having the laboratory incorporated into the TNO organisation. The continuous discussion of overlapping work and the organisation of the future tasks of the laboratories resulted in the decision to integrate both laboratories at one location. In parallel, TNO RVO became TNO Defence Research in 1980.
The laboratory building on the Waalsdorpervlakte was enlarged to accommodate the merge. On December 1, 1984, the (joint) new TNO Physics and Electronics Laboratory (TNO-FEL) started, exactly 57 years after defence research on the Plain of Waalsdorp. TNO-FEL continued in the following years as one of the three laboratories of the TNO Defence organisation in which the approach shifted to a more market-oriented approach based on military and civil needs of the domestic and foreign markets. The laboratory had five divisions:

  • Operations Research and Business
  • Command & Control and Simulation
  • Smart Sensor Solutions
  • Observation systems
  • Telecommunication and Security (mid-2003, a large part of the non-military activities in this area moved to TNO Telecom).
TNO location The Hague Waalsdorp - the 1969 part and the 1984 extension
TNO location The Hague Waalsdorp – the 1969 part and the 1984 extension

On 31 December 2005, TNO decided to end the individual TNO institutes (laboratories) as independent organisational units. TNO-FEL was merged into TNO core’s area TNO Defence and Security. On 1 January 2011, another reorganisation took place. The TNO core area structure was abolished and TNO was transformed into a “single”- TNO in which the areas of expertise that are located at location The Hague Waalsdorp work to a large extent for the unit Defence, Safety and Security.

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