There is a project electrosense.org to use massive numbers of globally distributed, Rpi + RTL + a special, inexpensive, wideband upconverters to cover the RF spectrum from almost DC to 6 GHz. Tied together by the Internet they collect this spectrum and post it to a shared database. The device code is OS and the database openly accessible. The spectrum analysis code, not yet. Tied together with a massively parallel computing system it could play an important role in open SIGINT and help develop open covert wireless technologies.