Within the framework of the cooperation with the Delft University of Technology, a full size testing facility has been designed and constructed on the premises of TNO FEL, in order to perform controlled radar experiments. The testing facility has been completed in July 1997. It is located in the dunes directly behind the TNO-FEL building, on a location that was formerly known as the "EMP site" where electromagnetic pulse experiments were once carried out.
The test facility consists of a buried wooden box. The dimensions of this box are 10 m x 10 m wide and 3 m deep (300 cubic meters). The box has been fully dug in into the ground, hence the bottom of the box is located three meters below the ground level. Special care has been taken not to use any metal parts in the construction of the box or in the vicinity thereof. The sandbox is filled with clean (reasonably homogeneous) river sand from the (Dutch) Caland canal. In order to keep the condition of the sand in the box optimal and to prevent pollution from the outside (for example ground water) entering the box, a drainage system was installed and the inside of the box was covered with a watertight plastic lining. To prevent the weather from influencing the test conditions and to protect the measuring equipment, a large tent covers the entire site. Additionally, a wooden shed is available for storage of personal computers and measurement equipment. While filling the box with sand, special care was taken to get a homogeneous profile. Current tests indicate that this was reasonably successful and good enough to work with.
At some stage in the future it is envisaged to empty the box and refill it with a different soil composition. To facilitate the measurement of EM transmissions into the ground a square PVC tube running from the surface of one side to the bottom of the other side has been installed about one meter from the edge of the sandbox. The next page shows a few pictures (taken during the construction phase) detailing some of the features of the facility.