"Steve House" wrote:
Hate to sound dense but how do you fly an NDB approach without an ADF?

Old answer: RDF. At least in the marine world, this was the predecessor
to the ADF. I'm assuming this was true in the aviation world too?
Stands for Radio Direction Finder (as opposed to Automatic Direction
Finder). Same principle, the difference being with the RDF, you have to
manually turn the antenna to find the strongest signal. The workload
involved pretty much requires a dedicated radio operator or navigator.

New answer: GPS