Getting a quadcopter stable in the air isn’t trivial. Stability of a quadcopter relies on the harmonious working of all of it’s parts.
The ArduPilot Mega supports serial communication between the quadcopter and a computer. This serial communication is used to upload the software, change tuning settings and to update the flight path. The ideal wireless solution is XBee. XBee modules are available at different frequencies and power outputs. I am using the XBee 2.4GHz 1mW with the wire antenna modules. The XBee 2.4GHz modules are more than sufficient for initial setup, tuning and short range use. The XBee 2.4GHz modules operate at the same frequency as microwave ovens, WiFi routers and just about any other wireless consumer device. These modules have to contend with radio interference and this why they are not ideal as a robust long range solution. For applications requiring longer range and robust communication, using the XBee Pro modules is a better solution. The XBee Pro’s operates at 900MHz the lower frequency allowing for a longer transmission range for the same power output as the 2.4GHz modules and are less susceptible to interference. The XBee Pro’s are offered in different power outputs. The higher the power output, the longer the transmission range.