1. Einleitung
The Radiomaster XR3 Nano Multi-Frequency ExpressLRS Receiver is a compact and versatile receiver designed for remote control applications, offering robust signal stability and extended range. It supports both 2.4GHz and Sub-G 900MHz frequency bands, making it suitable for various setups. This manual provides essential information for the proper installation, operation, and maintenance of your XR3 receiver.

Image 1.1: Radiomaster XR3 Nano Multi-Frequency ExpressLRS Receiver with connected dual-band antennas.
2. Sicherheitshinweise
Please refer to this instruction manual before use. Improper handling or installation may lead to equipment damage or personal injury. Ensure all connections are correct and secure before powering on the device. This product is recommended for users aged 18 years and up.
3. Funktionen
- Antennenvielfalt: Utilizes two antennas for improved signal stability and extended range, featuring a Skyworks RFX2401C for enhanced receiver performance and telemetry.
- Unterstützung mehrerer Frequenzen: Operates on both 2.4GHz and Sub-G 900MHz bands.
- Hochleistungs-Mikrocontroller: Equipped with an ESP32C3 microcontroller.
- Advanced Transceiver: Features a Semtech LR1121 transceiver.
- Zusätzliche Konnektivität: Includes an additional UART port and secondary port for advanced functionality.
- Easy Soldering: Designed with castled pads for convenient soldering.
- Integriertes WLAN: Built-in WiFi for effortless configuration and firmware updates via an intuitive WebUI
- Kompaktes Design: Ultra-compact dimensions (22mm x 15mm x 4mm) and lightweight (1.3g without antennas).

Bild 3.1: Überview of the XR3 receiver highlighting its multi-frequency, antenna diversity, LR1121, and ExpressLRS features.
4. Packungsinhalt
Überprüfen Sie, ob alle Artikel in Ihrem Paket vorhanden sind:
- 1 * XR3 Nano Multi-Frequenz Antenne Diversity ExpressLRS Empfänger
- 2 * T Antenna (Either 2.4GHz, 900Mhz, or Dual-band, depending on selected package)
- 1 * CRSF-Draht
- 3 * Schrumpfschlauch
- 1 * manuelle Karte
5. Einrichtung
5.1 Physische Verbindung
Connect the XR3 receiver to your flight controller or other compatible device using the provided CRSF wire. Ensure correct polarity and pin assignments for 5V, TX (Transmit), and RX (Receive).
- 5V: Power input (DC 4.5-8.4V)
- Sender: Telemetry data output from receiver
- Empfang: Control data input to receiver

Bild 5.1: Nahaufnahme view of the XR3 receiver board, indicating the 5V, TX, and RX pads for connection.
5.2 Antenneninstallation
Carefully connect the two T-antennas to the IPEX-1 connectors on the receiver board. Ensure they are securely attached. Position the antennas to maximize signal reception, typically at a 90-degree angle to each other for optimal diversity.
5.3 Bindung (Paarung)
The XR3 receiver uses the ExpressLRS protocol for binding. Follow these general steps:
- Power on your receiver three times, cycling power quickly. The LED on the receiver should flash rapidly, indicating it is in bind mode.
- On your ExpressLRS compatible transmitter, initiate the binding process. Refer to your transmitter's manual for specific instructions.
- Nach erfolgreicher Kopplung leuchtet die LED am Empfänger dauerhaft, was eine erfolgreiche Verbindung signalisiert.
Alternatively, the XR3 features a bind button. Press and hold the bind button while powering on the receiver to enter bind mode. The receiver also supports binding via WiFi.

Bild 5.2: Draufsicht view of the XR3 receiver board, showing the location of the bind button.
5.4 Firmware-Updates
The XR3 receiver supports firmware updates via its built-in WiFi. Connect to the receiver's WiFi network using a PC or mobile device and access the WebUI to manage settings and update firmware. Ensure you are using the correct firmware target: "RadioMaster XR3 2.4/900 Diversity RX".
6. Betrieb
6.1 Frequenzauswahl
The XR3 receiver is capable of operating on either 2.4GHz or Sub-G 900MHz frequencies. The type of antenna included with your package determines the primary operating frequency. If you have a dual-band antenna, the receiver can switch between 2.4GHz and 900MHz without requiring an antenna change. Ensure your transmitter is configured to match the receiver's operating frequency.

Image 6.1: The XR3 receiver supports various antenna types for 2.4GHz, Sub-G 900MHz, or Dual-Band operation.
6.2 ExpressLRS Functionality
Once bound, the XR3 receiver will communicate with your ExpressLRS transmitter, providing control and telemetry data. The antenna diversity feature automatically selects the best signal from the two antennas, enhancing link quality and range, especially in challenging RF environments. The telemetry power output is 100mW.

Image 6.2: The XR3 receiver incorporates a Low-Noise amplifier to boost sensitivity and a Power amplifier for extended telemetry range.
7. Wartung
The XR3 receiver is designed for durability, but proper care can extend its lifespan:
- Halten Sie den Empfänger sauber und frei von Staub, Schmutz und Feuchtigkeit.
- Setzen Sie den Empfänger nicht über längere Zeit extremen Temperaturen oder direkter Sonneneinstrahlung aus.
- Ensure antenna connections are secure but do not overtighten.
- Regularly check for any visible damage to the board or antennas.
8. Fehlerbehebung
If you encounter issues with your XR3 receiver, consider the following:
- No Bind: Ensure the receiver is in bind mode (rapidly flashing LED) and your transmitter is attempting to bind on the correct ExpressLRS firmware version and frequency. Check power connections.
- Poor Signal/Range: Verify antenna connections and positioning. Ensure no obstructions are blocking the signal path. Check for local RF interference. Confirm the correct frequency band (2.4GHz or 900MHz) is selected on both receiver and transmitter.
- Keine Telemetrie: Check the TX/RX wiring between the receiver and flight controller. Ensure CRSF protocol is correctly configured in your flight controller and transmitter.
- Receiver lässt sich nicht einschalten: Stromversorgungslautstärke prüfentage (DC 4.5-8.4V) and polarity. Inspect for any short circuits or damaged components.
9. Spezifikationen
| Spezifikation | Detail |
|---|---|
| Artikel | XR3 Nano Mehrfrequenz-Antennendiversitäts-ExpressLRS-Empfänger |
| Typ | ISM2.4, FCC915 |
| MCU | ESP32C3 |
| RF-Chip | LR1121 |
| HF-Anschluss | IPEX-1 X 2 |
| Antenne | 2x T-Antenna (2.4GHz, 900Mhz, or Dual-band) |
| Frequenzbereich | 2.4GHz / Sub-G 900MHz |
| Telemetrieleistung | 100 mW |
| Maximale Empfangsaktualisierungsrate | DK500Hz / K1000Hz |
| Minimale Empfänger-Aktualisierungsrate | 25 Hz |
| Arbeitsvolumentage | DC 4.5-8.4V |
| Gewicht | 1.3g (ohne Antenne) |
| Dimension | 22 mm * 15 mm * 4 mm |
| Firmware Version | ExpressLRS v3.5.1 vorinstalliert |
| FW-Ziel | RadioMaster XR3 2.4/900 Diversity-Empfänger |
| Busschnittstelle 1 | CRSF |
| Busschnittstelle 2 | UART |

Image 9.1: LR1121 Receiver Frequency Chart, showing compatibility across different XR models.

Image 9.2: ExpressLRS Dual-band Mode Compatibility Chart, detailing modulation modes and frequency bands for various modules.
10. Garantie und Support
Informationen zur Garantie und zum technischen Support finden Sie auf der offiziellen Radiomaster-Website. webBesuchen Sie unsere Website oder wenden Sie sich an Ihren autorisierten Händler. Bewahren Sie Ihren Kaufbeleg für eventuelle Garantieansprüche auf.