I have a pair of 900 XSC S3B xbee pros and a couple 2.1 dBi duck antennas. I just did a simple outdoor range testing and only got about 2,000 feet. I was outdoors without any buildings in the way, but there were a few small things between me and the other radio. That's the range expected for indoors or an urban environment....however, I'm going to need something better/stronger/further.
The basic idea for what I'm trying to do is build something to communicate location between two bicycles at Burning Man. There will be an arrow mounted on each bike (mine and my girlfriend's), and at any point one of us can press a button and the arrow will point in the direction of the other. So each bike will need to be constantly transmitting it's location to the other.
Burning man is a temporary camp-city in the dessert that is 5 miles wide with ~60k people. There are no cement structures but many camps, RVs and wood structures. Most camp structures are under 15 feet tall.
How can I make this project work? Are there a better RF transceivers and/or antennas that I should be using? Would upgrading the 2.1dBi duck antennas to a 8 dBi whip antennas help, even in non-line of site operation? I'm thinking of putting a repeater at the top of a 20 foot pole, however, it will still wont always be perfectly line of sight with each devices at all times.