The Radio telemetry system base on 3DR Radio system and 100% compatible.

It's designed as an open source Xbee replacement radio set, offering a lower price, longer range (approx one mile) and superior performance to Xbee radios. It’s available in 915Mhz and 433Mhz; and in the following configurations:  serial board (for the air) and USB (for the ground).

The system provides a full-duplex link  using HopeRF's HM-TRP modules running custom, open source firmware.  Interface to the module is via standard 5V-tolerant TTL serial / FTDI USB serial.

Firmware upgrades and configuration are fully supported in the APM Mission Planner. Configuration is also possible through the 3DR Radio configurator and AT commands.

◆Features

•Small size and light weight

•915MHz

•Receiver sensitivity to -121 dBm

•Transmit power up to 20dBm (100mW)

•Transparent serial link

•Air data rates up to 250kbps

•MAVLink protocol framing and status reporting

•Frequency hopping spread spectrum (FHSS)

•Adaptive time division multiplexing (TDM)

•Support for LBT and AFA

•Configurable duty cycle

•Built in error correcting code (can correct up to 25% data bit errors)

•Demonstrated range of several kilometers with a small omni antenna

•Can be used with a bi-directional amplifier for even more range

•Open source firmware

•AT commands for radio configuration

•RT commands for remote radio configuration

•Adaptive flow control when used with APM
•Based on the HopeRF HM-TRP radio module, featuring an SiLabs Si1000 RF microcontroller.

Datasheets of HM-TRP module: http://www.hoperf.com/upload/rf_app/HM-TRP.pdf
Documentation: http://code.google.com/p/ardupilot-mega/wiki/3DRadio
Radio Configurator(Air module need a USB-UART tool like FTDI to configure): http://vps.oborne.me/3drradioconfig.zip