It has been interesting to read about Google's plans to deliver internet via a fleet of helium balloons.
Despite the scepticism from some parts, it has real potential.
Indeed, broadcasting from flying and floating platforms is not new.
The US have used "stratovision" to broadcast TV in rural areas and war zones for half a century.
Closer to home, and closer to what Google are doing, the Serval Project and the Horus demonstrated helium-lofted mesh network nodes at Linux Conference Australia 2011 just after the Brisbane down-town area was flooded, to enable local mobile communications -- potentially including internet:
The main difference is we used a relatively small tethered balloon, partly because of cost (our budget was $100 including helium), and partly because we were using Wi-Fi communications instead of dedicated commercially licensed spectrum.
But like Google, we also gained some experience working with the Civil Aviation Authority here in Australia, because the conference venue was in the flight path to Brisbane airport.
While we only lofted the balloon to about 50m, way too low to cause actual trouble to air traffic, we wanted to do the right thing, so contacted Brisbane air traffic control. The result was the first time my activities have shown up on a NOTAM ("Notice to All Airmen"):
OBST TETHERED UNLIT WX BALLOON
PSN 220 MAG 8.35NM FM BRISBANE VOR
SFC TO 400FT AGL
FROM 01 262335 TO 01 270500
Watching the video you will see that it is quite a feasible way to provide communications. For me one of the very satisfying points was seeing people who had never used mesh communications before trying it out, and understanding it's potential to help in times of need, e.g., following disaster.
Note that our mesh communications and telephony software has advanced a long way from what is shown in the video.
If we were running the test again, we would loft one of our new prototype Mesh Extender units that use a UHF radio in an ISM band (similar rules as for the 2.4GHz Wi-Fi band) as well as Wi-Fi and could feasibly operate at higher altitude, and provide communications over many kilometres.