RadioMaster ER3 PRO PWM - Dual-Band GEMINI and GEMINI-X Receiver
by RadioMaster

The RadioMaster ER3 PRO PWM - Dual-Band GEMINI and GEMINI-X Receiver is a compact, high-performance ExpressLRS receiver engineered for space-constrained fixed-wing aircraft, glider fuselages, and surface vehicles requiring uncompromised link reliability. Powered by dual Semtech LR1121 transceivers operating on GEMINI-X RF architecture, the ER3 PRO simultaneously utilizes both 2.4GHz and Sub-G 900MHz frequency bands to provide true dual-band diversity and exceptional interference immunity.

Despite its streamlined form factor, the ER3 PRO acts as a versatile control hub with 3 amplified PWM channels, CRSF and SBUS serial outputs, and an external locking UART port for telemetry and system expansion. It features independent multi-source voltage telemetry with dedicated ADC channels for monitoring both receiver supply voltage (V-PWM up to 12V) and main flight batteries (EXT-V up to 70V). Housed in a durable injection-molded casing with secure MMCX antenna connectors, it transmits up to 100mW of telemetry power for maximum feedback range.

Key Features

• Dual-Band GEMINI-X RF Architecture: Simultaneously operates across 2.4GHz and Sub-G 900MHz bands via dual LR1121 transceivers for true diversity and link stability.

• 3 Amplified PWM Outputs + Serial Support: Delivers 3 direct servo PWM channels alongside CRSF and SBUS serial protocols for flexible airframe integration.

• Up to 100mW Telemetry Power: Transmits real-time link and telemetry data back to the transmitter with adjustable output power up to 100mW via ExpressLRS LUA script.

• Dual-Source Voltage Telemetry: Dedicated ADC channels independently monitor receiver supply/ESC BEC voltage (V-PWM up to 12V) and external main battery packs (EXT-V up to 70V).

• Locking Connectors for High Vibration: Built-in locking JST connectors on external UART and EXT-V telemetry ports prevent unintended disconnections.

• Secure MMCX Antenna Connectors: Heavy-duty MMCX ports allow easy replacement and maintenance of the included high-sensitivity antennas.

• Wi-Fi WebUI & Wireless Configuration: Supports direct wireless configuration, parameter tuning, and firmware updates without disassembling the receiver from tight bays.

Technical Specifications

• Brand / Manufacturer: RadioMaster

• Model Identifier: ER3 PRO PWM Dual-Band GEMINI and GEMINI-X Receiver

• RF Chipset: Dual Semtech LR1121 Transceivers

• Wireless Protocol: ExpressLRS (Requires ExpressLRS v4.1.0 or higher)

• RF Architecture: Dual-Band GEMINI-X (2.4GHz + Sub-G 900MHz)

• Output Channels: 3x PWM Channels

• Serial Protocol Support: CRSF / SBUS

• Input Voltage Range: DC 5.0V – 12.0V

• EXT-V Detection Range: DC 4.0V – 70.0V (2-Pin JST-GH Port)

• V-PWM Detection Range: Up to 12.0V DC

• Telemetry RF Output Power: Up to 100mW (Configurable via LUA script)

• Bus Interface: CRSF

• Antenna Connectors: MMCX (Secure, detachable)

• Antenna Array: 25cm High-Sensitivity Antennas

• Firmware Device Target: RadioMaster Dual 2.4GHz/900MHz Receiver

• Device Target Name: ER3Pro Dual Band True Diversity + 3xPWM RX

• Dimensions: 49.2 mm × 26.8 mm × 13.0 mm

• Net Weight: 13.5 grams (without antennas)

What Is Included

• (1) RadioMaster ER3 PRO PWM Dual-Band GEMINI-X Receiver

• (2) 2.4GHz High-Sensitivity Antennas (MMCX)

• (2) Dual-Band High-Sensitivity Antennas (MMCX)

• (1) External Voltage Telemetry Cable (EXT-V Type-B)

• (1) CRSF Serial Connection Cable

• (1) ELRS RX to SBUS Connection Cable