2.4 GHz Radio Module:

Comprehensive Guide to Long-Range IoT, LoRa & Zigbee Solutions – Coral RF

Introduction: The Ubiquitous 2.4 GHz Band

The 2.4 GHz ISM (Industrial, Scientific, and Medical) band is the most widely used license‑free frequency spectrum in the world. It powers Wi‑Fi, Bluetooth, Zigbee, Thread, Matter, and countless proprietary wireless systems. For engineers building IoT devices, industrial telemetry systems, smart home products, or remote control applications, the 2.4 GHz band offers a globally harmonised, readily available foundation for wireless communication.

But not all 2.4 GHz radio modules are created equal. The choice of modulation—LoRa for extreme range, (G)FSK for reliable telemetry, FLRC for high‑speed data, or IEEE 802.15.4 for Zigbee mesh networks—determines the range, data throughput, power consumption, and interference immunity of your final product.

Coral RF, a global supplier of high‑performance IoT wireless modules and gateways, offers a comprehensive portfolio of 2.4 GHz radio modules. Built on industry‑leading chipsets from Texas Instruments (CC2538, CC2652) and Semtech (SX1280), these modules cover a wide spectrum of applications: from ultra‑long‑range LoRa links to robust Zigbee mesh networks, from high‑power telemetry to low‑power sensor nodes. With output power up to +30 dBm (1 Watt), sensitivity down to -132 dBm, and support for multiple modulation schemes, Coral RF‘s 2.4 GHz modules deliver the flexibility and performance required for today’s most demanding wireless designs.

Part 1: Coral RF‘s 2.4 GHz Module Portfolio

Coral RF specializes in the research, development, and production of Sub‑1GHz and 2.4 GHz RF solutions based on Texas Instruments wireless MCUs and Semtech RF transceivers. In the 2.4 GHz space, Coral RF offers two distinct product families: SX1280‑based LoRa modules for long‑range point‑to‑point communication, and CC2538‑based Zigbee modules for mesh networking and smart home applications.

SX1280-Based LoRa Modules: N406AS and N407AS

The SX1280 from Semtech is a long‑range, low‑power 2.4 GHz transceiver with ranging capability. It is the first ISM band transceiver IC to integrate time‑of‑flight (ToF) functionality, opening up applications for asset tracking and location services. The SX1280 supports three modulation schemes: LoRa® for long‑range spread‑spectrum communication, FLRC for high‑data‑rate links, and (G)FSK for backward compatibility and reliable telemetry. It achieves an outstanding receiver sensitivity of -132 dBm and consumes as little as 5.5 mA in receive mode.

Coral RF has integrated the SX1280 into two powerful 2.4 GHz modules: the N407AS (+22 dBm output) for balanced long‑range performance, and the N406AS Pro (+30 dBm, 1 Watt) for extreme‑range applications.

N407AS: Balanced Long‑Range LoRa Module

The N407AS is a high‑performance, long‑range 2.4 GHz wireless communication module based on Semtech‘s SX1280 transceiver IC, enhanced with an integrated power amplifier. Operating in the global 2.4 GHz ISM band, it leverages LoRa® modulation to achieve an excellent balance of range, data rate, and power consumption.

The N407AS is designed for applications that require a reliable, long‑range wireless link without the complexity of external RF design. Its integrated power amplifier eliminates the need for external PA/LNA circuits, reducing BOM cost and PCB area. The module fully supports LoRa®, FLRC, and (G)FSK modulations, allowing engineers to optimise the link for range, data rate, or power consumption as needed. All SX1280 pins are accessible for deep customisation and secondary development.

The N407AS is particularly well‑suited for industrial IoT sensors, agricultural telemetry, asset tracking, drone control, and long‑range remote monitoring systems where multi‑kilometre range is required but 1 Watt output is not necessary.

N406AS Pro: Extreme‑Range 1 Watt LoRa Module

For applications demanding the absolute maximum communication range and link robustness, the N406AS Pro combines Semtech‘s SX1280 transceiver with an integrated high‑efficiency power amplifier (PA) and matching network, delivering a formidable output power of up to +30 dBm (1 Watt). This design, paired with the core chip‘s exceptional -132 dBm sensitivity, creates an unparalleled link budget exceeding 162 dB.

The N406AS Pro is the ultimate plug‑and‑play RF solution for achieving ultra‑long‑range, license‑free communication in the globally accessible 2.4 GHz ISM band. The integrated PA eliminates the need for external RF amplification design, enabling reliable multi‑kilometre links with a simple, single‑component solution. One hardware design operates worldwide on the 2.4 GHz band, simplifying logistics, inventory, and product certification efforts. The high link budget ensures excellent performance in non‑line‑of‑sight (NLOS), urban, and industrial environments where other wireless technologies fail.

Power supply design for the N406AS Pro requires careful attention: the integrated PA requires a stable 5V supply capable of providing up to 1A peak current during high‑power transmission.

The N406AS Pro is ideal for extreme‑range industrial telemetry, long‑haul drone links, remote infrastructure monitoring, and professional LoRa applications where maximum coverage area is the primary requirement.

CC2538-Based Zigbee Modules: N706AS and N711AP

Beyond LoRa‑based point‑to‑point links, Coral RF offers a complete family of 2.4 GHz Zigbee modules for mesh networking, smart home, and industrial automation. These modules are based on Texas Instruments‘ CC2538 wireless MCU—a powerful 48 MHz ARM Cortex‑M3 processor with up to 512 KB flash and 32 KB RAM, combined with a robust IEEE 802.15.4 radio.

N706AS: High‑Power Zigbee Module

The N706AS is a Zigbee module designed for 2.4 GHz mesh networking applications such as Zigbee routers and gateways. It combines the TI CC2538 wireless MCU with a CC2592 power amplifier, delivering +22 dBm output power at 250 kbps with a receiver sensitivity of -100 dBm [14†L2-L5].

The N706AS integrates a powerful ARM Cortex‑M3 processor with ample flash and RAM, enabling the module to run full Zigbee PRO network stacks, handle OTA firmware updates, and manage security protocols without external memory. The module is suitable for China, EU, and US 2.4 GHz ISM bands. All CC2538 pins are brought out, including the USB 2.0 interface, facilitating secondary development and customisation.

The N706AS is ideal for Zigbee coordinators, routers, gateways, smart lighting controllers, HVAC systems, and building automation networks requiring reliable mesh communication with extended range.

N711AP: Zigbee USB Dongle

For rapid prototyping, field testing, and gateway applications, Coral RF offers the N711AP—a compact USB Zigbee dongle based on the TI CC2538.

The N711AP integrates the CC2538, a USB‑to‑serial converter chip, a PCB antenna, a tactile switch, and dual‑colour LED indicators in a compact enclosure, making it suitable for mass production. It is plug‑and‑play—when connected to a PC or Raspberry Pi, it appears as a serial device and can be controlled via AT commands or directly accessed as a Zigbee network processor. The N711AP is widely used as a Zigbee gateway or edge router for smart home platforms, as well as for private network gateways and development testing.

Broader 2.4 GHz Ecosystem: CC2652 and Multi‑Protocol Solutions

Beyond the modules detailed above, Coral RF‘s 2.4 GHz portfolio also includes products based on TI‘s CC2652 series—a multi‑protocol wireless MCU supporting Thread, Zigbee, Matter, Bluetooth 5.2 Low Energy, IEEE 802.15.4g, 6LoWPAN, TI 15.4‑Stack (2.4 GHz), and concurrent multi‑protocol operation through a Dynamic Multiprotocol Manager (DMM) driver. The CC2652 family, with its integrated 48 MHz ARM Cortex‑M4F processor and up to 704 KB flash, is ideal for advanced multi‑protocol gateways, Thread border routers, and Matter devices.

Coral RF provides CC2652‑based USB dongles and modules, enabling developers to build products that simultaneously support Zigbee and Bluetooth LE, or act as Thread border routers for Matter‑compatible smart home ecosystems.

Part 2: Understanding the SX1280 – The Heart of Coral RF‘s Long‑Range 2.4 GHz Modules

The Semtech SX1280 is a long‑range, low‑power 2.4 GHz transceiver with three modulation options: LoRa®, FLRC, and (G)FSK. It achieves a receiver sensitivity of -132 dBm, consumes as little as 5.5 mA in receive mode, and operates from 1.8 V to 3.7 V. It is the first ISM band transceiver IC to integrate a time‑of‑flight (ToF) ranging engine, enabling precision distance measurement between two radios for tracking and localisation applications.

Modulation Options Explained

LoRa® (Long Range) – A chirp spread spectrum (CSS) modulation that spreads a narrowband signal across a wider bandwidth using frequency chirps. This processing gain pushes sensitivity down to -132 dBm, allowing signals to be decoded even when they are below the noise floor. LoRa achieves multi‑kilometre range at 2.4 GHz while consuming very little power. Data rates in LoRa mode range from 0.3 kbps to 500 kbps, software‑programmable via spreading factor and bandwidth settings.

FLRC (Frequency Modulated Continuous Wave with Linear Chirp) – A high‑data‑rate modulation option that supports up to 2 Mbps, suitable for applications requiring both range and throughput, such as low‑latency video transmission or high‑speed telemetry.

(G)FSK – The digital version of FM, providing good noise immunity and moderate data rates. GFSK offers backward compatibility with legacy 2.4 GHz systems and is widely used in industrial telemetry and remote control applications.

Ranging Engine

The SX1280‘s built‑in ranging engine measures the time‑of‑flight (ToF) between two radios, enabling distance measurement without requiring GPS. This feature opens up applications in asset tracking, drone collision avoidance, indoor localisation, and security systems where knowing the distance between devices is as important as the data itself.

Regulatory Compliance

The SX1280 is fully compliant with all worldwide 2.4 GHz radio regulations, including EN 300 440 (Europe), FCC CFR 47 Part 15 (USA), and ARIB STD‑T66 (Japan). Coral RF‘s SX1280‑based modules inherit this compliance, simplifying global product certification.

Part 3: Comparing Coral RF‘s 2.4 GHz Module Families

The key decision factors between these product families are:

• N406AS Pro vs. N407AS: Choose the N406AS Pro when maximum range is critical and you can accommodate the higher power supply and current requirements. Choose the N407AS for a balanced solution with lower power consumption and simpler integration.

• SX1280 series vs. CC2538 series: Choose SX1280‑based modules for long‑range, low‑data‑rate point‑to‑point or star‑topology networks. Choose CC2538‑based modules for mesh networking, smart home ecosystems, or when standard Zigbee protocol is required for interoperability with existing devices.

• N706AS vs. N711AP: Use the N706AS when embedding Zigbee functionality into a custom PCB. Use the N711AP USB dongle for rapid prototyping, field testing, or as a ready‑to‑use gateway connected to a PC or Raspberry Pi.

Part 4: Applications of Coral RF 2.4 GHz Radio Modules

Long‑Range Industrial Telemetry (SX1280 Series)

Oil and gas pipelines, water distribution networks, and remote environmental monitoring stations often span tens of kilometres. Coral RF‘s N406AS Pro, with its +30 dBm output power and -132 dBm sensitivity, provides the link budget necessary for reliable communication over such distances. The module‘s LoRa modulation ensures robust performance even in non‑line‑of‑sight conditions, penetrating vegetation, urban obstacles, and industrial structures.

Smart Agriculture

Agricultural sensors—soil moisture probes, weather stations, tank level monitors—are distributed across large fields and farms. The N407AS offers an optimal balance of range (over 1000 m) and power consumption (80 mA TX current), enabling battery‑powered sensors to operate for years. The module‘s programmable data rate allows engineers to trade off range for throughput as needed.

LoRaWAN Gateways and Private LPWAN

When building a private LoRaWAN network for campus‑ or city‑wide IoT coverage, the N406AS Pro can serve as the RF front‑end for a LoRaWAN gateway. Combined with a Raspberry Pi or industrial Linux computer running ChirpStack or The Things Network packet forwarder, a single Coral RF module can cover a radius of several kilometres, connecting hundreds of LoRa sensors.

Zigbee Mesh Networking (CC2538 Series)

For smart lighting, HVAC control, occupancy sensing, and building automation, Zigbee‘s self‑healing mesh network is the industry standard. Coral RF‘s N706AS provides the processing power and RF performance to act as a Zigbee coordinator, router, or end device. With +22 dBm output power, it can cover large residential and commercial buildings without requiring repeaters in every room.

Smart Home Gateways (CC2538 USB Dongles)

The N711AP USB dongle is widely used as a Zigbee coordinator for open‑source smart home platforms such as Home Assistant (via zigbee2mqtt). Its USB interface and compact form factor make it easy to deploy—simply plug it into a Raspberry Pi or home server, and the system gains the ability to control Zigbee lights, sensors, switches, and thermostats.

Drones and RC Systems

ExpressLRS—an open‑source RC link based on the SX1280—has revolutionised long‑range FPV drone racing and aerial videography. Coral RF‘s N407AS and N406AS Pro modules are fully compatible with ExpressLRS firmware, which can be flashed onto custom hardware. The firmware supports packet rates from 25 Hz to 500 Hz and achieves ranges well over 100 km with 2.4 GHz hardware when properly optimised.

Asset Tracking and Localisation

The SX1280‘s built‑in ranging engine enables time‑of‑flight distance measurement between two radios. A pair of Coral RF N407AS modules can be used to estimate distance without GPS, making them suitable for indoor asset tracking, warehouse inventory management, and drone collision avoidance systems.

Healthcare and Wearables

The ultra‑low power consumption of the SX1280 (5.5–8.6 mA RX current, 0.2–1.8 µA sleep current) allows for miniature battery‑operated medical devices and wearables. The small footprint of Coral RF modules (as small as 20×17×3 mm) fits easily into space‑constrained designs.

Part 5: How to Choose the Right 2.4 GHz Radio Module

Step 1: Define the Communication Topology

• Point‑to‑point (one transmitter, one receiver) → SX1280‑based modules

• Star network (one gateway, multiple end devices) → SX1280‑based modules

• Mesh network (self‑healing, multi‑hop) → CC2538‑based Zigbee modules

Step 2: Determine Range Requirements

Step 3: Evaluate Data Rate Needs

• Low data rate (<100 kbps) → SX1280 in LoRa mode, ideal for sensor uplinks

• Medium data rate (250 kbps) → CC2538 Zigbee or SX1280 in GFSK mode

• High data rate (up to 2 Mbps) → SX1280 in FLRC mode

Step 4: Consider Power Constraints

• Battery‑powered end device (years of life) → N407AS in LoRa mode with deep sleep (<1 µA)

• Line‑powered gateway → N406AS Pro (1W) or N706AS

• USB‑powered gateway → N711AP USB dongle (bus‑powered)

Step 5: Choose Host Interface

• SPI (direct low‑level control) → N406AS Pro, N407AS, N706AS

• UART (AT command simplicity) → N706AS

• USB (plug‑and‑play, no MCU required) → N711AP

Step 6: Factor in Protocol Stack Development Effort

• Custom proprietary protocol → SX1280‑based modules, full flexibility

• Open‑source LoRaWAN → SX1280‑based modules, use existing stacks

• Zigbee PRO (certified interoperability) → CC2538‑based modules, TI Z‑Stack provided

• ExpressLRS (RC link) → SX1280‑based modules, open‑source firmware available

Part 6: Integration and Development Tools

SPI Interface (N406AS, N407AS, N706AS)

All Coral RF 2.4 GHz SMD modules expose a standard 4‑wire SPI interface (SCK, MOSI, MISO, CS) for configuration, control, and data transfer. The SPI bus supports clock speeds up to 16 MHz, providing sufficient bandwidth for even the highest data rate modes.

For the SX1280‑based modules, the radio driver system abstracts low‑level register configuration, FIFO management, and interrupt processing. Open‑source libraries such as RadioLib (C++) provide cross‑platform support for the SX1280 on Arduino, STM32, ESP32, and Raspberry Pi platforms.

UART AT Command Interface (N706AS)

The N706AS supports UART control with an AT command set, allowing developers to configure frequency, output power, network parameters, and transmit/receive data without writing low‑level SPI drivers. This dramatically reduces development time for engineers who want to focus on application logic rather than RF protocol details.

USB Virtual COM Port (N711AP)

The N711AP USB dongle appears as a standard serial device (/dev/ttyUSB0 on Linux, COMx on Windows) when connected to a host. It can be controlled via AT commands or by directly accessing the CC2538‘s memory through the USB interface. This makes it ideal for rapid prototyping, PC‑based gateway applications, and field testing.

ExpressLRS Firmware

For RC and drone applications, the open‑source ExpressLRS firmware can be flashed onto custom hardware using the SX1280. The firmware supports packet rates from 25 Hz to 500 Hz, telemetry return, and dynamic power control. Coral RF‘s N407AS and N406AS Pro modules are compatible with ExpressLRS hardware targets, enabling hobbyists and engineers to build professional‑grade RC links with multi‑kilometre range and sub‑10 ms latency.

TI Z‑Stack (CC2538)

For Zigbee applications, Texas Instruments provides the Z‑Stack software development kit, a complete implementation of the Zigbee PRO protocol stack. Z‑Stack runs directly on the CC2538‘s ARM Cortex‑M3 processor and includes sample applications for coordinator, router, and end device roles. Coral RF‘s N706AS module is fully compatible with Z‑Stack, allowing engineers to leverage TI‘s thoroughly tested network stack rather than developing a proprietary mesh protocol from scratch.

USB Dongles as Development Tools

Beyond their role as end‑product components, Coral RF‘s USB dongles serve as powerful development and debugging tools. The N711AP can be configured as a packet sniffer, capturing Zigbee packets from any device in the network and displaying them on a PC for protocol analysis. The N711AP is also used as a Zigbee coordinator for open‑source platforms like zigbee2mqtt, enabling integration of dozens of Zigbee sensors and actuators into Home Assistant and other smart home systems.

Part 7: 2.4 GHz vs. Sub‑1 GHz – Understanding the Trade‑off

While this article focuses on 2.4 GHz solutions, engineers often face the choice between 2.4 GHz and Sub‑1 GHz ISM bands. Coral RF offers both families, allowing engineers to select the optimal frequency band for each application.

The choice is not always exclusive. Many advanced systems use 2.4 GHz for high‑bandwidth local communication and Sub‑1 GHz for long‑range backhaul. Coral RF‘s comprehensive portfolio across both bands enables hybrid architectures that leverage the strengths of each frequency range.

Conclusion: The Right 2.4 GHz Radio Module for Every Application

Coral RF‘s 2.4 GHz radio module portfolio covers the full spectrum of wireless applications—from extreme‑range LoRa telemetry to high‑density Zigbee mesh networks, from 1 Watt industrial gateways to plug‑and‑play USB dongles for rapid prototyping.

• N406AS Pro (+30 dBm, 1W) – The ultimate choice for maximum range. Ideal for long‑haul telemetry, remote gateways, and professional LoRa applications where coverage area is the primary constraint. Requires careful power supply design (1100 mA TX current) but delivers an unmatched link budget exceeding 162 dB.

• N407AS (+22 dBm) – The balanced workhorse for industrial IoT, agricultural sensors, and long‑range point‑to‑point links. With -132 dBm sensitivity and sub‑1 µA sleep current, it offers excellent performance without the power supply complexity of the 1W module. Perfect for battery‑powered devices that need multi‑kilometre range.

• N706AS (+22 dBm Zigbee) – The mesh networking specialist. Built on TI‘s powerful CC2538 ARM Cortex‑M3, it runs full Zigbee PRO stacks and supports Thread, 6LoWPAN, and IEEE 802.15.4. Ideal for smart home coordinators, building automation routers, and industrial mesh networks.

• N711AP USB Dongle (+7 dBm) – The rapid development and gateway tool. Plug into any PC or Raspberry Pi, and you have an instant Zigbee gateway for open‑source platforms like zigbee2mqtt. Also serves as a field‑ready packet sniffer and debugging tool.

Whether you are a hardware engineer integrating a module into a custom PCB, a software developer building a LoRaWAN gateway, or a smart home enthusiast setting up a Zigbee network, Coral RF provides the 2.4 GHz radio module, documentation, and ecosystem support to get your project from concept to production.

This article is intended for embedded systems engineers, IoT developers, RF product designers, and smart home integrators evaluating 2.4 GHz wireless solutions for industrial, commercial, and consumer applications.