http://engineeringtv.com/blogs/etv/archive/2009/06/24/starfighter-integrated-repeater-payload.aspxSpace Data's StarFighter Repeater Platform, currently in use by the United States Air Force, extends the range of standard issue military two-way radios from 10 miles to nearly 500 miles. The concept is simple: fill a balloon with helium or hydrogenenCommunityServer 2007.1 (Debug Build: 20917.1142)