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LR24 Telemetry Radio User Manual

Introduction

LR24 is a series of long-range telemetry radios developed, designed, and manufactured by MicoAir Tech. Operating in the 2.4 GHz ISM band, it uses LoRa spread-spectrum and FHSS frequency-hopping technologies to provide strong interference resistance and high receiver sensitivity. It supports full-duplex transparent serial transmission and is compatible with mainstream open-source flight controllers and ground control station software. It can connect ArduPilot/PX4 flight controllers to ground control stations such as Mission Planner/QGC, and can also carry data between an RTK base station and rover.

Purchase

MicoAir Tech Store

Model Information

  • LR24-F-Mini: Maximum transmit power 27dBm, without enclosure (receiver-board form factor)
  • LR24-F: Maximum transmit power 27dBm
  • LR24-P: Maximum transmit power 30dBm

All models use a CP2102 USB-to-TTL chip except the LR24-F-Mini, which does not include an onboard USB-to-TTL chip.

The models have different transmit power levels and can all be paired with one another, but the communication range is generally determined by the lower-power radio in the link.

Specifications

  • Operating frequency band: 2400-2482MHz

  • Transmit power: 1000mW(LR24-P); 500mW(LR24-F/F-Mini)

  • Selectable transparent transmission rates: 2.4 kB/s(default); 4 kB/s; 8 kB/s; 20 kB/s;

  • Maximum single serial packet length: 20 kB

  • Communication interfaces: LVTTL (3.3V) serial; USB-Type-C

  • Serial baud rate: 57600 by default

  • Antenna connector: SMA (external thread, female center contact)

  • Supply voltage: 4.5-5V

  • Maximum average power consumption: 3W(LR24-P); 2W(LR24-F/F-Mini)

Dimensions

  • LR24-F-Mini dimensions, in mm
  • Weight: 2.5g

Interfaces

The LR24-F/P telemetry radios have two external interfaces:

  • A 3.3V-level TTL serial interface with a GH1.25-4P connector, normally used to connect directly to a flight controller serial port.
  • A USB-Type-C port for connection to a computer. The corresponding USB-to-TTL driver must be installed on the computer. Note that the USB port cannot be used to connect directly to a flight controller.

  • Tx: Serial Tx; connect to the flight controller's serial Rx
  • Rx: Serial Rx; connect to the flight controller's serial Tx
  • 5V: 5V power input
  • GND: Power GND

The LR24-F-Mini has one external interface:

  • A 3.3V-level TTL serial interface with an SH1.0-4P connector, normally used to connect directly to a flight controller serial port.

  • Tx: Serial Tx; connect to the flight controller's serial Rx
  • Rx: Serial Rx; connect to the flight controller's serial Tx
  • 5V: 5V power input
  • GND: Power GND

Configuration Software and Drivers (How to Configure Radio Parameters)

Use MicoAssistant to connect to the radio and configure its parameters: MicoAssistant download and user guide

USB-to-TTL driver

LED Indicator

The LR24 has one green LED that primarily indicates the telemetry connection status:

  • Flashing at 1Hz: Telemetry link not connected
  • Solid: Telemetry radios paired and connected normally

Pairing the Telemetry Radios

Two LR24 modules automatically connect after power-up when their parameters match (all modules ship with the same default parameters). If multiple radio pairs must operate at the same time, assign a different module address to each pair. See the parameter descriptions below for details.

Telemetry Parameters

Operating Mode

The LR24 supports three operating modes: full duplex, broadcast-transmit, and broadcast-receive. Full-duplex mode is the default.

Only full-duplex mode can be used for flight controller telemetry. In broadcast-transmit or broadcast-receive mode, a radio can only transmit or receive data; these modes are generally used with RTK base stations and rovers.

Transparent Transmission Rate

The LR24 supports four rate modes: 2.4 kB/s(default); 4 kB/s; 8 kB/s; 20 kB/s. The 20K mode uses FLRC modulation; all other modes use LoRa modulation.

Frequency Mode

The LR24 supports four frequency modes: manual, automatic, FHSS-GROUND, and FHSS-AIR.

Automatic mode is the default and selects the communication frequency automatically. In manual mode, the frequency parameter must be set manually.

FHSS is the frequency-hopping mode and is recommended for flight controller telemetry. Configure the radio connected to the flight controller as FHSS-AIR and the radio connected to the computer as FHSS-GROUND.

Communication Frequency

This parameter is effective only in manual frequency mode.

Values 0-82 correspond to 2400-2482MHz.

Module Address

The default value is 1000. Two modules can communicate only when their address parameters match. When using multiple telemetry pairs simultaneously, assign each pair a different value in the range 1-30000.

Serial Baud Rate

Baud rate of the GH1.25 interface. Supported values are 9600/19200/38400/57600/115200/230400/460800/921600; the default is 57600.

When using the 8K/s transparent transmission mode, the baud rate must be set to 115200 or higher. When using the 20K/s mode, the baud rate must be set to 921600.

USB Baud Rate

Baud rate of the USB-Type-C interface. Supported values are 57600/115200/921600; the default is 57600.

When using the 8K/s transparent transmission mode, the baud rate must be set to 115200 or higher. When using the 20K/s mode, the baud rate must be set to 921600.

Telemetry Configuration Guides