RadioMaster XR3 Nano Dual Band Diversity ELRS Receiver

The RadioMaster XR3 Nano is an ExpressLRS receiver built on Semtech's LR1121 transceiver, so one board can run on either 2.4GHz or sub-GHz 900MHz, with two antenna ports for true antenna diversity. This version comes with dual-band T-antennas, so you can switch bands in the configuration without changing hardware. It suits 5" freestyle and long-range quads, wings and any build where you want 900MHz penetration on some days and 2.4GHz packet rates on others.

Key features

• LR1121 transceiver with an ESP32C3 MCU; runs on 2.4GHz or 900MHz, one band at a time.

• Antenna diversity across two IPEX-1 (U.FL) connectors keeps the link steady when one antenna is shadowed by the frame or battery.

• Skyworks RFX2401C front end adds an LNA for receive sensitivity and a PA for up to 100mW telemetry.

• CRSF on the main port plus an additional UART for advanced functions; castellated pads for direct soldering.

• Built-in Wi-Fi for WebUI configuration and firmware updates; ships with ExpressLRS 3.5.1 on the RadioMaster XR3 2.4/900 Diversity RX target.

Specifications

• RF chip: Semtech LR1121

• MCU: ESP32C3

• Bands: 2.4GHz ISM / 900MHz (FCC915)

• Antenna connectors: 2 × IPEX-1 (U.FL)

• Antennas: 2 × dual-band T-antenna

• Telemetry power: up to 100mW

• Refresh rate: 25Hz to 1000Hz

• Working voltage: 4.5–8.4V DC

• Bus interfaces: CRSF + UART

• Weight: 1.3g (without antennas)

• Dimensions: 22 × 15 × 4mm

• Firmware: ExpressLRS 3.5.1 pre-installed

Bind it to an ExpressLRS transmitter on matching 3.x firmware and the same band; a 900MHz link needs a 900MHz-capable or LR1121-based TX module. Wire it to a free UART on the flight controller and set the receiver protocol to CRSF.