Hobbypower Radio Wireless Telemetry Kit 433mhz Module for MWC Multiwii Apm2.6 Apm2.5.2 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. 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.