Eisbär radar station

The Second World War was an important turning point for aviation. For the first time, part of the battle was also fought in the air, and fighters, bombers and paratroopers were tactical components of the army. Whoever controlled the airspace had a great military advantage. Initially, German aircraft were superior. In the autumn of 1940, the German Blitzkrich lost momentum, and it was the British Royal Air Force’s turn to bomb ports and industrial and civilian targets in Germany, including Wilhelmshaven and Bremen. From 1943, targets such as Berlin and Hamburg also became important.  

An important approach route to Germany passed over Friesland. Although navigation technology was in full development, pilots were largely dependent on landmarks in the landscape. The Wadden Sea, the Afsluitdijk and the IJsselmeer were clearly visible from the air.  

The Germans were also aware of the importance of the Frisian approach route, and they quickly set up searchlights and anti-aircraft guns. The airfield in Leeuwarden was an important part of the defence system. From there, German fighters took off to intercept enemy bombers as quickly as possible. 

From 1941, the defence line was extended with radar stations near Sondel ('Eisbär') and on Terschelling ('Tiger') and Schiermonnikoog ('Schlei'). The advanced radar stations could determine the height, speed and course of both enemy aircraft and their own night fighters. They were part of the Kammhuber Line, an extensive defence network that stretched from Norway to southern France. 

The defensive line was a great success. Many planes were shot down over Friesland, and about 1 in 3 airmen did not return. On 16 April 1945, the “Eisbär” radar station’s work ended abruptly. That morning, farmers from the surrounding area were called upon to help evacuate the camp. When the Dutch Forces of the Interior entered Sondel the next morning, everything was in ruins. The radar devices and associated stone buildings had been blown up with explosives. One day later, camp Sondel was repurposed as an internment camp for NSB members and collaborators from Friesland.