OTH radars work by literally bouncing the signal off the ionosphere. To achieve a processable return, the transmitters must have considerable power. Thus, OTHs are normally Early Warning/Ballistic Missile Defense systems.
There's also OTH targeting, which works by launching below the victim radar's dead-zone, (caused by earth curvature, and other terrain), a buddy is illuminating the target, acquires the missile and provides terminal guidance. Kind of an early 80's tactic, used by the Soviets for anti-ship missions. Now with TLAM, CALCM etc, they can basically do their own targeting.
It's not necessarily a counter-stealth technique if that's what you mean. BUT, used in conjunction with a bi-static design, it could theoretically detect certain "stealthy" aircraft (and ships for that matter.) A Bi-static radar has at least two geographically separate transmitters controlled by a single processing system.
Retired F4 WSO. This is all unclas, and available in radar textbooks and reference material