Air watch tower Post 7 X 3

The Air Guard Tower Post 7 X 3 was commissioned by the Air Guard Corps (part of the Air Defence Command) of the Ministry of Defence in 1953. It was designed by Hague architect M. Zwaagstra, who founded the NV Raatbouw especially for this purpose. The tower, type 1848, is constructed from prefabricated reinforced concrete elements manufactured at the NV Schokbeton in Kampen. Height and construction of the towers varied and depended on local conditions. The tower in Echten (location Hees) is 18.48 metres high and is located in a wooded area in Hees, near Echten and is surrounded by tall trees. The tower was part of a nationwide network of 276 air guard posts, of which some 139 were purpose-built between 1951 and 1955. The names also indicated the location: 7 (= Groningen Air Guard Circle), X (= circle of towers), 3 (= serial number of the post within the circle). The distance between posts never exceeded 16 kilometres because 8 kilometres was the maximum distance at which aircraft could be located by ear.

The system of air watch towers was established during the Cold War in the 1950s-60s as a warning system for enemy aircraft (from the Soviet Union) which, when flying below 1,500 metres, could not be spotted by radar at the time. Only two such towers remain in Drenthe, both of which are in the process of being designated as protected provincial monuments. Around 1968, the tower lost its function. Anno 2009, the tower is owned by the Forestry Commission and is used for telecommunications. Notable structural detail is the use of buttresses, which were fitted to only a few of the towers due to their relatively high height. Furthermore, a number of authentic components such as the wooden staircase and the observation cabin with the turntable of the air watch apparatus are still reasonably intact.

The castellated construction system was used in the 1950s for the construction of farm sheds in the Noordoostpolder, an engineer barracks in Raamsdonksveer and a test house in Kampen, among other things. The system made it quick and easy to build a structure on site and allowed for easy disassembly and possible reuse.