NDBs/ADF are much more common outside the US, where there isn't a huge installed...

tjohns 4 months ago | parent | context | favorite | on: Decoding DME aircraft radio navigation system with...

NDBs/ADF are much more common outside the US, where there isn't a huge installed VOR network or where there is a need for long-range airways over remote terrain. (Canada, I'm looking at you.)