Amateur radio enthusiasts in the US will be interested in Faraday, an open-source digital radio that runs on 915 MHz, which amateur radio enthusiasts may know better as the 33 cm band. You can transmit on 915 MHz without a license (in the US), taking advantage of the Industrial, Scientific, and Medical (ISM) exemption.

via Put That Amateur Radio License to Use on 915 MHz — Hackaday