http://www.wired.com/2015/09/balloon-spy-probe-deep-sweep/ I was thinking about something like this, about 25 years ago.  But rather than a free-flying balloon, I felt that an aerostat configuration would be better.  Further, I figured that a bidirectional optical fiber link would be useful, such as:  http://datainterfaces.com/sfp-modules-single-strand-bidirectional-gigabit-SC... An otherwise-unjacketed optical fiber, but with a woven Kevlar strength covering, would be useful.   Obviously, the FAA wouldn't approve, but that doesn't keep us from imagining, huh?               Jim Bell.