FLR-9
The AN/FLR-9 is a type of very large circular "Wullenweber" antenna array, built at many locations during the cold war for HF/DF direction finding of high priority targets. The worldwide network, known collectively as "Iron Horse", could locate HF communications almost anywhere on the planet. Due to their large size and shape, these units were often nicknamed "Elephant Cages" or "Turkey Farms".
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