I'd be leery of using an ADF at night. It's a low-frequency device and suffers from "night effect" otherwise known as sky-wave, which comes at it from above rather than from the direction of the NDB. It might be OK very close in, but I'd prefer a VOR or (dare I say it) a GPS.
Near the coast, or in hilly terrain, there's no way I'd rely on an ADF for anything at night.