Wullenweber circularly-disposed antenna arrays (CDAAs) are large HF direction-finding antennas, sometimes colloquially referred to as "elephant cages", that were popular in the Cold War. They allowed the bearing of an incoming signal to be located to perhaps 0.5° (for the US Navy's AN/FRD-10). I've been fascinated by them ever since I saw the one on the Silver Strand south of San Diego, California. Dozens were built all over the world. Now nearly all have been demolished. The Wikipedia article for the US Air Force's AN/FLR-9 says "advances in technology have made the FLR-9 obsolete."
What advances in technology made Wullenweber CDAAs obsolete? What technologies are used for military HF direction finding now?
EDIT: I'm talking about fundamental advances in technology. I presume if the technology were still broadly useful, then the electronics would be modernized. To rephrase the question, why do modern militaries not use giant circular antenna arrays for HF direction finding any more? What do they use instead?