>>> To oversimplify things: US Northern Command is in charge of monitoring and defending the US, Canada, and Mexico, while NORAD (a joint US-Canada operation) is in charge of monitoring and defending the airspace of the US and Canada. Needless to say, they played a big, disputed role in the events of 9/11.
Our friends over at Government Attic obtained and posted audio of the NORAD/USNORTHCOM radio channels on that day. With their blessing, The Memory Hole 2 has posted these files to the Internet Archive, meaning that you can now stream them online, download them as a torrent, or download the individual files in MP3 or open Ogg Vorbis formats. (To download them as zipped MP3 files, go the Government Attic's PDF.)
There are 21 files, each one covering approximately 6 hours and 40 minutes on one channel, for a total of 140 hours.
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