MicoAir LR900-A 915MHz LoRa Telemetry Radio for Pixhawk / ArduPilot / PX4 — Budget Long-Range Pair

Overview

The MicoAir LR900-A is the budget model in the LR900 series of long-range 915MHz LoRa telemetry radios for drones and robotics. Operating in the 890–915MHz band with 160mW (22dBm) transmit power and LoRa spread-spectrum modulation, it provides a reliable bidirectional MAVLink link between your Pixhawk / ArduPilot / PX4 flight controller and a ground station running Mission Planner or QGroundControl.

It is plug and play: a pair ships with matching default parameters and connects automatically at power-up — no configuration needed for standard flight-controller telemetry. Transparent serial transmission means it carries any serial protocol, not just MAVLink.

Band planning tip: the LR900-A transmits at 915MHz, so pair it with a 2.4GHz RC link (e.g. ELRS 2.4G) on your aircraft — avoid running it alongside a 915MHz RC receiver (ELRS 915 / TBS Crossfire).

Features

• 915MHz band (890–915MHz), LoRa spread-spectrum modulation for strong anti-interference performance
• Transmit power up to 22dBm (160mW), low power draw (max average 300mW)
• Point-to-point full-duplex link, plus broadcast modes for RTK base/rover correction streams
• Transparent serial transmission with adjustable baud rate — compatible with any data and protocol
• Dual interfaces: 3.3V TTL serial (JST-GH) + USB Type-C (CH340 USB-to-UART)
• Compact bare-board design for easy integration
• Plug and play: a pair links automatically out of the box (solid green LED = connected)

LR900-A vs LR900-F — which one?

• Transmit power: LR900-A is 22dBm (160mW); the LR900-F is 27dBm (500mW) — choose the F for maximum range.
• FHSS: the LR900-A supports manual/auto frequency modes only; FHSS frequency hopping is available on the F/P models.
• USB chip: the LR900-A uses CH340 (the F uses CP2102) — so the LR900-A does not work with Mission Planner on Android.
• Enclosure: the A is a bare board; the F comes in a case.

Full side-by-side comparison in the LR900 User Manual — model variants.

Specifications

Data Transmission

• Air data rate: 2.1 KB/s (default) / 1.1 KB/s / 0.4 KB/s
• Maximum single-packet length: 4 KB
• UART baud rate (JST-GH port): 9600 / 19200 / 38400 / 57600 (default) / 115200
• UART baud rate (USB port): 57600 (default) / 115200

Electrical

• Supply voltage: 4.5–5V DC (from USB or JST-GH)
• Maximum average power consumption: 300mW
• Serial interface: 3.3V TTL UART, JST-GH1.25-4P
• USB interface: USB Type-C (CH340)
• Antenna connector: SMA (female)

Regional note: in the U.S. and Canada the commonly used 915MHz ISM band is 902–928MHz. You are responsible for operating only on frequencies and power levels permitted in your region.

Getting Started

Two LR900-A radios with default settings bind and connect automatically after power-on — the green LED turns solid when the link is up. Wire one radio to your flight controller's TELEM port, connect the other to your PC via USB-C, and open Mission Planner or QGroundControl.

Step-by-step setup guides (wiring, flight-controller parameters, ground-station connection, troubleshooting):

• ArduPilot Telemetry Setup Guide (Mission Planner)
• PX4 Telemetry Setup Guide (QGroundControl)

Note: the LR900-A uses the CH340 USB chip — install the CH340 driver (not CP2102) on Windows before the radio appears as a COM port. Running multiple pairs in one area? Give each pair its own module address (1–30000, default 1000).

Documentation & Guides

• LR900 User Manual — full specs, model variants (A / F / P), pinout & all parameters
• LR900 Web Configurator Guide — changing parameters in the browser
• ArduPilot Telemetry Setup Guide
• PX4 Telemetry Setup Guide
• 915MHz or 2.4GHz? LR900 vs LR24 comparison

Package List

• LR900-A Telemetry Radio Module × 2
• 915M 2dBi antenna (11 cm) × 2
• 20 cm GH1.25-4P to GH1.25-6P cable (for Pixhawk 4/5/6) × 1
• 20 cm GH1.25-4P to MX1.25-6P cable (for Pixhawk 1/2) × 1
• 20 cm GH1.25-4P to SH1.0-4P cable (for MicoAir 405/743) × 1

Technical Support

If you encounter any issues or need technical support after receiving your product, contact us at support@robofusion.net — our support team responds within 48 hours.