915MHz 100mW Ground Data Module Telemetry Kit for Pixhawk and APM Flight Controllers - SiK Firmware, MAVLink, FHSS, and -121dBm Sensitivity for UAV Ground Station Communication
The 915MHz 100mW Ground Data Module Telemetry Kit is a compact, lightweight UAV telemetry radio pair operating on the 915MHz ISM band, built around the HopeRF HM-TRP wireless module with a Silicon Laboratories Si4432 RF transceiver and Si1000 8051 microcontroller, and running open-source SiK firmware for direct compatibility with Pixhawk, APM, and PX4 flight controllers via APM Mission Planner and MAVLink-based ground station software. At 20dBm (100mW) transmit power with receiver sensitivity reaching -121dBm, this kit offers a notably high sensitivity figure relative to its output power class, improving the effective link budget and usable communication range beyond what the transmit power figure alone would suggest, with a specified communication distance of 2,624.7 feet (approximately 800m) under standard conditions and extended range achievable with a small omnidirectional antenna or an optional external bi-directional amplifier. The -121dBm receiver sensitivity places this kit at the higher end of the sensitivity range for 100 mW-class 915 MHz telemetry radios, making it well-suited for operations in environments where received signal strength is the limiting factor rather than transmit power.
The telemetry pair runs the same proven SiK firmware architecture used across the 3DR telemetry radio family, providing frequency hopping spread spectrum, adaptive time division multiplexing, MAVLink protocol framing, and a transparent serial link that passes MAVLink telemetry packets between the flight controller and ground station without protocol conversion or host-side driver requirements. The built-in error correcting code recovers up to 25% data bit errors without retransmission, maintaining link integrity under interference and marginal signal conditions. Air data rates reach up to 250kbps on the transparent TTL UART serial interface, supporting real-time parameter monitoring, in-flight PID tuning, waypoint management, and full MAVLink status reporting during flight. AT commands support local radio configuration and RT commands enable remote configuration of the air-side unit from the ground station without physical access to the UAV. Adaptive flow control, when used with APM, prevents serial buffer overrun under high telemetry data rate conditions, and LED indicators on both units provide visual connection status confirmation without requiring a serial terminal connection.
Key Features
- Frequency: 915MHz ISM band for UAV telemetry in North American and other 915MHz-permitted regulatory regions
- Transmit Power: 20dBm (100mW) for standard open-field UAV ground station communication
- Receiver Sensitivity: -121dBm, high-sensitivity front-end for improved effective link budget in the 100mW output power class
- Communication Distance: 2,624.7 feet (approx. 800m) under standard conditions, extendable with omnidirectional antenna or optional bi-directional amplifier
- Wireless Module: HopeRF HM-TRP module with Silicon Laboratories Si4432 RF transceiver and Si1000 8051 microcontroller
- 2-Way Half-Duplex: Bidirectional wireless communication between air-side TTL UART serial radio and ground-side unit
- Transparent Serial Link: Passes MAVLink telemetry packets without protocol conversion for direct Pixhawk, APM, and PX4 flight controller compatibility
- Air Data Rate: Up to 250kbps for real-time telemetry, parameter transfer, and MAVLink status message exchange
- MAVLink Protocol Framing: Native MAVLink framework and status reporting for direct Pixhawk, APM, and PX4 telemetry stream compatibility
- Frequency Hopping Spread Spectrum: FHSS improves RF interference resilience and co-channel contention resistance on shared 915MHz spectrum
- Adaptive Time Division Multiplexing: TDM optimises bidirectional channel sharing between air and ground radios under varying link conditions
- LBT and AFA Support: Listen Before Talk and Adaptive Frequency Agility reduce RF collision probability on shared 915MHz band
- Error Correcting Code: Built-in ECC recovers up to 25% data bit errors without retransmission for reliable telemetry under marginal link conditions
- Configurable Duty Cycle: Adjustable transmission duty cycle for regulatory compliance and co-existence with other 915MHz systems
- AT and RT Command Support: AT commands for local radio configuration and RT commands for remote air-side radio configuration from the ground station
- APM Adaptive Flow Control: Prevents serial buffer overrun under high telemetry data rate conditions when paired with APM flight controllers
- LED Indicators: Onboard connection status LED indicators on both air and ground units for visual link confirmation
- Bi-Directional Amplifier Compatible: Optional external bi-directional amplifier support for range extension beyond the standard 100mW output
- Open-Source Firmware: SiK open-source firmware with a bootloader supporting over-the-serial-interface firmware upgrades and APM Mission Planner configuration
Applications
- Pixhawk, APM, and PX4 flight controller real-time telemetry and parameter monitoring via APM Mission Planner or compatible MAVLink GCS software
- In-flight PID tuning, waypoint management, and MAVLink status monitoring over a 915MHz wireless link within standard communication range
- Fixed-wing and multirotor UAV ground station communication requiring a compact, lightweight 100mW 915MHz MAVLink telemetry pair
- UAV range extension builds using an optional external bi-directional amplifier or higher-gain omnidirectional antenna on the standard RP-SMA connector
- High-sensitivity 915MHz telemetry applications where -121dBm receiver sensitivity improves link reliability versus standard-sensitivity 100mW-class radios
- MAVLink-based autopilot builds requiring transparent serial telemetry with native MAVLink framing, FHSS resilience, and ECC error recovery.
Package List:
- 1 set 3DR 915Mhz 100mW radio telemetry module.
