Stealth, Countermeasures, and ELINT, 1960-1975 12 years ago
Another way is bi-static radars. Stealth is generally designed to prevent returns from going back to the sender, with the downside that they get scattered in all other directions. Just setup a (silent and difficult to locate) receiving station(s) and give it a communication channel to the sender (to synchronized), then it will receive the emissions from the sender that bounce off stuff.