Arduino Radio Module: Coral RF SX1262 LoRa Guide (5-15km)

Adding wireless communication to your Arduino projects opens up endless possibilities. This guide covers the essentials of Arduino radio modules, with a focus on Coral RF SX1262 modules—the latest generation of long‑range, low‑power LoRa technology.

1. What Is an Arduino Radio Module?

A radio module lets your Arduino send and receive data wirelessly. Most modules use a simple SPI or UART interface. You don’t need to be an RF expert – the module handles modulation, encoding, and error correction for you.

Popular frequency bands include Sub‑1GHz (315/433/868/915 MHz) and 2.4 GHz. Sub‑1GHz offers longer range and less interference than the crowded 2.4 GHz band.

2. Common Radio Module Types

Why choose SX1262 over older SX127x?
SX1262 consumes about 50% less power in receive mode (4.6 mA vs 10 mA), has built‑in +22 dBm output power, and offers better sensitivity (-148 dBm).

3. Coral RF: High‑Quality SX1262 Modules for Arduino

Coral RF (Shenzhen Heyan Technology) specialises in Sub‑1GHz modules based on Semtech SX1262 and TI chips. Their modules are Arduino‑friendly, with complete example code and documentation.

3.1 N401AS – Standard Low‑Power Module

• Chip: Semtech SX1262

• Frequency: 150–960 MHz (433/470/868/915 MHz)

• Output power: +22 dBm (built‑in)

• RX current: ~4.6 mA

• Sleep current: <0.2 µA

• Range: 5–10 km (line‑of‑sight)

• Interface: SPI, 3.3V logic

• Size: 16×16 mm

Perfect for battery‑powered IoT sensors, smart metering, and general long‑range telemetry.

3.2 N427AS – High‑Power (2W) Module

• Output power: +33 dBm (2W) with external PA/LNA

• Range: Up to 15 km+

• Supply: 3.3–5V (works with 5V Arduinos)

• Size: 36×24 mm

Ideal for drone control, long‑range monitoring, and applications that need maximum reach.

4. Connecting Coral RF SX1262 to Arduino

Wiring (N401AS to Arduino Uno – use level shifters for 5V boards!) :

Important: SX1262 uses 3.3V logic. For 5V Arduinos, use a logic level converter on all SPI lines. The BUSY pin must be connected.

5. Software Setup (Arduino)

The easiest way to start is with the RadioLib library (install via Library Manager).

Transmitter Example

#include<SPI.h>#include<RadioLib.h>#defineNSS10#defineNRST9#defineBUSY8SX1262 radio =newModule(NSS, NRST, BUSY);voidsetup(){
  Serial.begin(9600);
  radio.begin(868.0);// 868 MHz for Europe
  radio.setOutputPower(22);// +22 dBm}voidloop(){
  radio.transmit("Hello from Arduino!");delay(5000);}

Receiver Example

#include<SPI.h>#include<RadioLib.h>#defineNSS10#defineNRST9#defineBUSY8SX1262 radio =newModule(NSS, NRST, BUSY);voidsetup(){
  Serial.begin(9600);
  radio.begin(868.0);
  radio.startReceive();}voidloop(){
  String message;int state = radio.readData(message);if(state == RADIOLIB_ERR_NONE){
    Serial.print("Received: ");
    Serial.println(message);
    radio.startReceive();}}

6. Choosing the Right Module

7. Quick Tips for Maximum Range

• Use the lowest data rate (e.g., SF12)

• Set output power to +22 dBm (or +33 dBm on N427AS)

• Use a good antenna tuned to your frequency

• Keep modules elevated and away from metal

8. Where to Buy

• Coral RF official website: www.coralradio.com

• Email: info@coralradio.com

9. Summary

Coral RF’s SX1262 modules offer a modern, power‑efficient way to add long‑range wireless to Arduino projects. The N401AS is great for most battery‑powered IoT applications (5‑10 km), while the N427AS delivers 15 km+ when you need extreme reach. With simple SPI wiring and the RadioLib library, you can have a working LoRa link in minutes.