This site in the small village of Predefin in the Pas de Calais region, inland of Boulogne-sur-Mer and Calais, has a chequered history which has left it with a strange mix of buildings.
Construction began in early 1943 under the supervision of Organisation Todt and the German Army with the plans to build a radar and radio guidance base in support of the new V2 wonder weapons.
The constructions took place in two separate sites to the south of the village – one for radar to monitor the V2s rockets launched from Eperlecques and La Coupole to the north… and the second site to control the flight of these huge missiles.

Known as ‘Leitsstrahl’, the flight control system used a series of radio beams to correct the path of a V2 rocket in the first minute of its flight towards its target.
There is a site constructed for the same purpose at Roquetoire – to the south east of La Coupole - although this is essentially one large garage bunker which was used to protect mobile radio guidance equipment for steering V2s.

As development of the V2 technology continued and the gyroscopes within the rockets improved, the planned use of the sites was redundant by early 1944, even though construction was completed.
At the start of 1944, the German Army handed the complex over to the Luftwaffe who set about extending and would use it as a radio tracking base for the Pas de Calais region.

At the south east site, they constructed buildings for two Wurzburg radars, a protected building for a Freya radar, several transmitter and receiving antennas, and a massive ‘Z’-shaped, 100m long personnel building which included offices, a huge communications centre, and hospital. To the south were more office buildings pleas kitchen, toilets, barrack blocks, a garage, and air-raid shelters.
At its peak, over 600 personnel are believed to have been stationed at the site.

The grand scale of the building wasn’t to be replicated at the south west site which would become the location for a large radar – the Mammut – and several small personnel bunkers.
Supported by a huge, multi-room L485 type bunker, this 25m wide, 10m high early warning radar array could track targets up to 300km away at an altitude of 8,000m.
Inside the building was housed advanced technology for the time including ‘Seeburg’ electronic plotting tables as well as comms and crew rooms.

As with many large bunker locations in the Pas de Calais region, Predefin was subjected to a series of heavy bombing raids. To counter this, a dummy radar site with a fake Mammut radar was constructed around a 2km east of the village.
The Predefin site was abandoned in September 1944 as Allied forces moved north towards Boulogne and Calais.
The site is on private farmland and permission must be sought before visiting.