Testing out my home built DIY 5.8ghz helical today. I guess its working great because I went out further than I've ever gone to 3.3 miles (5.3km) without a single lose of signal!
IBCrazy's guide for building a helical antenna:
http://www.rcgroups.com/forums/showth...
This flight took place 32km / 20 miles away from the nearest airport and out of the way of commercial full scale flight paths. Pretty much the middle of nowhere. I would never try flying this high closer to populated areas and/or airports.