VRX Radio Module lite – 868 Mhz (Europe)

The VRX Radio telemetry system is 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 868Mhz (Europe and other countries that don’t allow 915Mhz); 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.

The SiK firmware includes a bootloader that permits radio firmware upgrades over the serial interface, and radio firmware with configurable parameters. Firmware upgrades and configuration are fully supported in the APM Mission Planner. Configuration is also possible through the Radio configurator and AT commands.

Hardware features and specifications

• Very small size
• Light weight (under 4 grams without antenna)
• Available in 868MHz or 433MHz variants
• Temperature range: from -20°C to +40°C
• Receiver sensitivity to -121 dBm
• Transmit power up to 20dBm (100mW)
• Transparent serial link
• Air data rates up to 250kbps
• Range of approx 1 mile
• 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