Back when I worked on skywave HF OTHR systems in the late 80s we knew that they could detect and pinpoint stealth aircraft easily. Most stealth systems are des

Back when I worked on skywave HF OTHR systems in the late 80s we knew that they could detect and pinpoint stealth aircraft easily. Most stealth systems are designed to either absorb or reflect millimetric point source radar. HF long wavelength systems reflect nicely off the top surfaces of the aircraft, which aren't designed to dissipate and absorb those frequencies. To one of those systems a stealth aircraft shows up brighter than a 747... So while this is neat science, it's not economical compared to the systems currently in use. The only real downside of OTHR systems is that you need a couple of miles space for the transmit antenna and a big empty space for the receiver; plus plenty of CPU to process the data.