I'm interested that it doesn't mention the nonlinear junction detector, but I'm no spyhunter or anything and maybe that's an obsolete piece of equipment now. After all, there's certainly a lot more innocent transistors and diodes out in the world today than there were during the cold war. Also I'm not sure they're legal for just anybody to use since they vomit so much radio interference.
Oh god. Yeah there's a fair share of weird junk on that site, which probably goes hand-in-hand with having the necessary paranoia to build your own nonlinear junction detector.
I found the link on Hackaday way back when, I have no idea about the rest of this shady IP address. Should have probably been more careful about posting something like this, but the electronics builds are so well documented.
An interesting build:
http://67.225.133.110/~gbpprorg/mil/non/index.html