Ask HN: Are there any projects to do historical archiving of RF spectrum?

Something like archive.org but for rf spectrum. I'm not even sure if its legal, but I was playing with my SDR the other day and thinking of all the historical information that passes over the airwaves that is ephemeral. Being able to view this data after a major event would be amazing. Imagine listening to all the radio information as 9/11 transpired or during the coup attempt in turkey.

Obviously this couldn't be done everywhere all the time, but it would be interesting to be able to archive radio spectrum during major events.

A quick google search didn't turn up anything.