The Deep Sweep: High Altitude Signal Research by The Critical Engineering Working Group (Julian Oliver, Bengt Sjölen, Danja Vasiliev) is an aerospace probe scanning the otherwise out-of-reach signal space between land and stratosphere, with special interest placed in UAV/drone to satellite communication.

Taking the form of a high-altitude weather balloon, tiny embedded computer and RF equipment, The Deep Sweep project is being developed to function as a low-cost, aerial signal-intelligence (SIGINT) platform. Intended for assembly and deployment by public, it enables surveying and studying the vast and often secretive world of signal in our skies. Two launches have been performed so far, from sites in Germany, landing in Poland and Belarus respectively.

More here.