Radio selection

Range was the most important factor to me in choosing a two-way data link for the plane. Even once it's out of video range, I want to know where the plane is and be able to upload new waypoints or bring it home.

There are a few options for cheap, long-range packet modems that operate in unlicensed bands. Here are some of the models I considered:

XBee Pro XSC900 MHz, 20 mile range, 100 mW, 9.6 kBps max data rate. Cost: $72
This one is limited by transmit power but seems very good otherwise. It was a tempting option because it's common and there are accessories and code already available.


AeroComm AC4790
900 MHz, 20 mile range, 1000 mW, 115 kBps max data rate. Cost: $74
I nearly decided on the AC4790 before learning about...


RFM DNT900
900 MHz, 40 mile range, 1000 mW, 460 kBps max data rate. Cost: $69
The DNT900, on paper, is obviously the winner. It also allows the user a lot of control over internal parameters, which will enable low latency and robust communication even at long range.

I bought two DNT900 radio modules from Mouser.