SX1278 LoRa Ra-02 433MHz Wireless Module

Long-range 433MHz LoRa spread-spectrum transceiver with high sensitivity for km-range low-power IoT telemetry over SPI.

₹400 + 18% GST

SKU: BOTBIT-IOT-08 · Best for: Long-range wireless sensor telemetry (soil, weather, tank level) in fields and remote sites

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Overview

About SX1278 LoRa Ra-02 433MHz Wireless Module.

The Ra-02 is a compact LoRa module built around Semtech's SX1278 transceiver, tuned for the 433MHz ISM band that is license-free for low-power use in India. It uses LoRa spread-spectrum modulation to trade data rate for range and link robustness, letting you push small telemetry packets several kilometres in open terrain while running on very little power. Communication with a host MCU is over a standard 4-wire SPI bus plus a few DIO/reset lines.

It is one of the most popular long-range radios among Indian makers and IoT developers because it is cheap, well documented, and works out of the box with mature Arduino and ESP32 libraries. Compared to cheap ASK 433MHz modules, the SX1278 gives you real link-level features: configurable spreading factor, bandwidth and coding rate, CRC, addressing and a receiver sensitivity down to around -148 dBm.

The Ai-Thinker Ra-02 board breaks out the SX1278 on a small PCB with an IPEX/U.FL antenna connector, so you must fit a 433MHz antenna (spring or SMA pigtail) before transmitting. It is a bare transceiver, not a plug-and-play LoRaWAN node, so you drive the radio and protocol yourself in firmware.

Key features

Why it stands out.

Semtech SX1278 LoRa transceiver operating in the 433MHz ISM band

LoRa spread-spectrum with configurable spreading factor, bandwidth and coding rate for long range

High receiver sensitivity down to about -148 dBm and up to +20 dBm (100mW) transmit power

Standard 4-wire SPI interface plus RESET and DIO0-DIO5 lines for easy MCU connection

IPEX/U.FL antenna connector (external 433MHz antenna required)

Low power operation with sleep/idle modes suited to battery telemetry nodes

Specifications

Selection facts.

Chipset	Semtech SX1278
Frequency band	410-525 MHz (433 MHz ISM typical)
Modulation	LoRa spread spectrum, also FSK/GFSK/OOK
Max transmit power	+20 dBm (100 mW)
Receiver sensitivity	Down to -148 dBm
Host interface	SPI (up to 10 Mbps) + DIO/RESET
Supply voltage	1.8-3.7 V (3.3 V typical)
Antenna connector	IPEX / U.FL
Line-of-sight range	Up to ~5-10 km in open terrain
Logic level	3.3 V (not 5 V tolerant)

Applications

Where it is used.

Long-range wireless sensor telemetry (soil, weather, tank level) in fields and remote sites
Point-to-point or star LoRa links between microcontroller nodes
Battery-powered IoT nodes needing km-range at low data rate
Home-brew LoRaWAN nodes with a suitable stack (e.g. LMIC)
Remote metering, gate/pump control and asset monitoring
Hobby projects like long-range remote sensors and mesh experiments

Buying guide

How to choose.

Choose the Ra-02 (433MHz) if you want the longest range and best obstacle penetration and your region/application allows 433MHz; pick a 868/915MHz LoRa module instead if you specifically need LoRaWAN gateway compatibility on those bands. The SX1278 is the 433MHz-family part, while its SX1276 sibling covers 868/915MHz.

Pair it with a 3.3V-logic MCU such as an ESP32, ESP8266, STM32 or a 3.3V Arduino. If you use a 5V Arduino (Uno/Nano), you must level-shift the SPI and DIO lines, since the module is not 5V tolerant. Always connect a matched 433MHz antenna before powering up, or you risk damaging the PA.

Buy two units minimum for any point-to-point link, and add an SMA pigtail plus antenna if you need better range than a spring wire. For a plug-and-play cellular-free long-range link, this is the go-to budget radio in India.

FAQ

Common questions.

Is the Ra-02 5V tolerant or do I need level shifting?

No, it runs at 3.3V and its pins are not 5V tolerant. With a 3.3V board (ESP32, ESP8266, STM32) you can wire it directly. With a 5V Arduino you must level-shift the SPI (SCK, MOSI, NSS) and DIO0 lines and power VCC from 3.3V.

Which library should I use with Arduino or ESP32?

The popular choices are the Sandeep Mistry 'LoRa' library for simple point-to-point links, or RadioHead's RH_RF95 driver. For LoRaWAN you would use the MCCI LMIC library. All of these support the SX1278 on SPI.

Do I need an antenna, and what happens without one?

Yes, you must fit a 433MHz antenna via the IPEX/U.FL connector before transmitting. Running the transmitter with no antenna reflects power back into the PA and can damage the module.

Can it do LoRaWAN and talk to a public gateway?

The chip supports LoRaWAN, but this 433MHz version is not compatible with the common Indian/EU 865-867/868MHz LoRaWAN gateways. Use it for private point-to-point links, or use an 868MHz module for LoRaWAN.

What real-world range can I expect?

In clear line of sight with a good antenna, high spreading factor and low data rate, several kilometres is realistic (5-10 km reported). In urban or indoor settings expect a few hundred metres, depending on obstacles and antenna placement.

What is in the box?

Typically just the Ra-02 module. Many Indian sellers do not include an antenna, so confirm the listing and order a 433MHz spring antenna or SMA pigtail separately if one is not bundled.