The AF would provide us with spectra and our engineers would try and duplicate that signal.
One engineer said they looked like badly tuned amplifiers.............
Great coincidence, I grew up with hearing my dad talk about such things, being called into the Pentagon to speculate on the capabilities of some radar based on the signals alone, especially after he retired and I started working as an engineer myself. Some of the crazy cold war stories about the Soviets he probably shouldn’t have been telling me were really interesting.