Wullenweber and other HFDF Sites

The Wullenweber Antenna is used for High Frequency radio Direction Finding (HFDF). It is a type of Circularly Disposed Antenna Array (CDAA) that's also known as a Circularly Disposed Dipole Array (CDDA). It had been nicknamed as the elephant cage. They were designed to receive radio signals between 2 and 32 MHz.

Most were built after WWII with the majority built in the Soviet Union and aligned countries. The antennas in the Soviet Union were called Krug (Russian for circle). There were numerous other designations used throughout the world such as FIX8, FIX24, Thick8, and others.

The U.S. military designations for the antenna and associated equipment was AN/FRD-9 (Army and Air Force), AN/FRD-10 (Navy), and AN/AX-16.

Wullenweber Antenna
AN/FRD-10 Wullenweber Antenna
Drawings of antenna construction

These two drawings taken from Wikipedia illustrate the physical construction of the antenna and the dimensions:

Wullenweber Antenna Wullenweber Antenna


The map below shows the location of all the CDAA antennas including the Wullenweber, Krug, and variants. If it's a circular, high-frequency direction finding antenna, it's intended to appear on this map.

FLR-10 blue marker   FLR-9 red marker   AX-16 yellow marker   KRUG brown circle   FIX8 gray circle   FIX24 green circle   FIX40 purple marker   THICK8 gold marker   Misc black circle


Youtube: The Last Elephant Cage

Federation of American Scientists: AN/FLR-9

Wikiwand: Wullenweber

Wullenweber Antenna Arrays

Soviet KRUG and other CDAAs