RadioMaster ER3 PRO PWM Dual-Band GEMINI & GEMINI-X Receiver

The RadioMaster ER3 PRO is a compact 3-channel PWM receiver featuring dual-band 2.4GHz and Sub-G 900MHz Gemini X technology. With up to 100mW telemetry output, dual voltage monitoring, and MMCX antenna connectors, it offers flexible connectivity for space-constrained RC installations.

Features

• ExpressLRS Performance: Low latency, high reliability, and excellent link quality with flexible configuration options.
• Dual-Band Gemini X (2.4GHz + Sub-G 900MHz): Utilizes both frequency bands to provide enhanced link reliability across a wide range of operating environments.
• Up to 100mW Telemetry Output: Increased telemetry output power for improved data reliability and range.
• 3 PWM Outputs + Serial Support: Compact PWM output with CRSF and SBUS options.
• External UART Port (Locking Connector): Dedicated interface for telemetry, external devices, and system expansion.
• Independent Multi-Source Voltage Telemetry: Monitor up to two power sources simultaneously using dedicated ADC channels: EXT-V (up to 70V), receiver supply voltage (V-PWM) (up to 12V).
• MMCX Antenna Connectors: Durable, replaceable antennas with a secure connection.
• Wi-Fi Updates & WebUI: Configure and update directly without disassembly.
• Durable Injection-Molded Housing: Compact, protective enclosure for long-term reliability.
• Application: A compact, full-featured receiver for models that require advanced RF performance, telemetry, and connectivity in a space-efficient package.
• Compatibility: Compatible with all ExpressLRS transmitters and modules, including radios with built-in ELRS. 

The ER3 PRO features ExpressLRS technology with dual Semtech LR1121 transceivers and Gemini X dual-band operation on 2.4GHz and Sub-G 900MHz. Telemetry output power is adjustable up to 100mW via LUA.

With 3 PWM outputs, CRSF/SBUS serial support, and two independent voltage monitoring channels, the ER3 PRO monitors receiver supply voltage up to 12V and external voltage from 4V to 70V. Locking connectors on the UART and EXT-V ports help keep connections secure.

MMCX antenna connectors allow for secure attachment and easy replacement, while the injection-molded housing protects the receiver in a compact form.

⚠️ Power Input & Voltage Notice

EXT-V Telemetry Input:

The maximum input voltage for the EXT-V external voltage telemetry reading is 70V. Do not exceed 70V, as this may damage the receiver.
The EXT-V input is accessed through the 2-pin JST-GH connector. Connect the red wire to the positive (+) terminal of the battery or ESC. The ER3 PRO provides independent ADC channels for EXT-V and receiver supply voltage (V-PWM).

Servo Power:

Ensure the ESC’s BEC can provide sufficient current for the servos being used. For high-voltage, high-torque servos, a 2S 7.4V battery or a suitable high-current UBEC is recommended.

Specification