Wullenweber
From Wikipedia, the free encyclopedia
The Wullenweber (correct spelling is Wullenwever), or Circularly Disposed Dipole Array (CDDA)/Circular Dipole Antenna Array (CDAA) is a large circular antenna array used by the military to triangulate radio signals for intelligence gathering and the occasional maritime rescue. The antenna is colloquially known as the elephant cage.
CDAA technology was developed by the German navy signal intelligence research and development center (Nachrichtenversuchsanstalt der Marine NVA) during the early years of World War II. The inventor of the system was NVA group leader Dr. Hans Rindfleisch, who worked after the war as a Technical Director for the northern Germany official broadcast (Norddeutscher Rundfunk - NDR). Technical team leaders were Dr. Pietzner, Dr. Schelhorse, and Dr. Wächtler. The latter was a co-founder of Plath Co and later a consultant to Plath and Telefunken (electronic companies). Although all men retired in West Germany, some of their second-echelon technicians were taken to the USSR after the war. This led to the Soviets deploying 20 CDAAs before the United States military became interested and developed their own version of the technology.
The original two systems were built by the Germans. The first CDAA was built at Joring in Denmark (it was destroyed following the war in accordance with the Geneva Convention). Dr. Wachtler arranged to have a second one built, at Telefunken expense, at Langenargen/Bodensee, for further experiments after the war.
In the years following the war, the U.S. disassembled the CDAA at Langenargen/. Bodensee and brought it back to the University of Illinois. Ed Hayden, a young engineer, led the reassembling of the CDAA and studied it. Three antenna designs came out of this study:
- AN/FLR-9 - used by the U.S. Air Force and Army;
- AN/FRD-10 - used by the U.S. Navy
- AN/FRD-13 - 'Pusher' System used primarily by the British.
In 1959 the first contract to build an AN/FLR-9 antenna receiving system was awarded to the Sylvania Corporation. The contract called for the completion of two AN/FLR-9 systems at San Vito AS, Italy and RAF Chicksands, United Kingdom. Both were completed in 1962.
Following the completion of these CDAAs, a second contract was awarded to Sylvania to build systems at Misawa AB, Japan and Clark AB, Philippine Islands; one in Pakistan (never built), one at Elmendorf AFB, Alaska, and one at Karamursel AS, Turkey. The last two were completed in 1966.
The U.S. Army awarded a contract in 1968 to F&M Systems to build two AN/FLR-9s; one at USASA Field Station Augsburg, Germany and one at Udon Thani, Thailand. Both were completed in 1970. The Army's version of the AN/FLR-9 has the same antenna design as the Air Force version, but the design of the delay lines in the Beam Forming Networks inside the Central Building are different. The Army used what is called a "Lamp Cluster" delay line design and the Air Force used a "Coaxial" delay line design.
The other five AN/FLR-9 systems have been dismantled:
- 1975 Udon Thani, Thailand following base closure;
- 1977 Karamursel AS, Turkey following a conflict over foreign aid to Greece;
- 1991 Clark AFB, Philippine Islands following the Mt. Pinatubo volcano eruption;
- 1993 San Vito, Italy following base closure;
- 1996 RAF Chicksands, United Kingdom following base closure.
As of 1996, only three AN/FLR-9 were left in operation around the world: the U.S. Air Force's at Elmendorf AFB, Alaska and Misawa AB, Japan, and the U.S. Army's in Augsberg, Germany. The one in Augsburg was turned over to the German Intelligence Service (BND) in 1998, while the others are believed to now be dismanteled.
