1. Introduction
The RADIOMASTER XR4 Gemini Xrossband Dual-Band Receiver is designed for remote control applications, offering reliable signal reception through its dual-band capabilities. It supports ExpressLRS Gemini Xrossband (Gem-X) protocol, operating on both 2.4GHz and Sub-G 900MHz frequencies. This manual provides essential information for the proper setup, operation, and maintenance of your XR4 receiver.
2. Contenu du colis
Vérifiez que tous les éléments énumérés ci-dessous sont inclus dans votre colis :
- 1 x XR4 Gemini Xrossband Dual-Band Receiver
- 2 x Dual-Band T-Antenna
- 1 x CRSF Wire
- 3 x Heat-Shrinkable Tube
This image displays the Radiomaster XR4 receiver board with its two dual-band T-antennas attached, illustrating the complete receiver assembly.
3. Caractéristiques
- True Diversity & Dual-Band: Utilizes dual LR1121 RF transceivers for enhanced reliability.
- ExpressLRS Gemini Xrossband (Gem-X) Compatible: Supports 2.4GHz and Sub-G 900MHz bands.
- Microcontrôleur haute performance : Equipped with ESP32D4.
- Dual Semtech LR1121 Transceivers: Provides robust signal processing.
- Secondary UART Port: For advanced functionality and future expansion.
- Castled Pads: Facilitates easy soldering.
- Module Wi-Fi intégré : Simplifies firmware updates and configuration via WebUI.
- Ultra-Low Latency & High Refresh Rate: Ensures stable RF link.
This image highlights the two Semtech LR1121 transceivers, which are central to the receiver's dual-band and true diversity capabilities.
Cette image montre un détail view of the XR4 receiver board, specifically pointing out the additional UART port available for future expansion and advanced functionality.
4. Spécifications
| Paramètre | Valeur |
|---|---|
| MCU | ESP32D4 |
| Puce RF | LR1121 x 2 |
| Connecteur RF | IPEX-1 x 2 |
| Antenne | Dual-Band T Antenna x 2 (Included) |
| Gamme de fréquences | 2.4GHz / Sub-G 900MHz |
| Puissance de télémétrie | 100 mW |
| Maximum Receive Refresh Rate | DK500Hz / K1000Hz |
| Fréquence de rafraîchissement minimale du récepteur | 50 Hz |
| Vol de travailtage | DC 4.5-8.4V |
| Poids (sans antenne) | 1.7g |
| Dimensions | 22 mm x 18 mm x 4 mm |
| Firmware Version (pre-installed) | ExpressLRS v3.5.1 |
| Cible FW | RadioMaster XR4 2.4/900 Gemini RX |
| Interface bus 1 | CRSF |
| Interface bus 2 | UART |
Cette image offre une vue claire de dessus. view of the XR4 receiver's circuit board, showing component layout and connection points.
Cette image montre un côté profile of the XR4 receiver board, with "XR4 V1.00" clearly visible, indicating the model and version.
5. Configuration et installation
5.1 Connexions de câblage
The XR4 receiver uses standard CRSF protocol for communication. Connect the receiver to your flight controller or other compatible device using the provided CRSF wire. Ensure correct polarity for power connections (DC 4.5-8.4V).
- 5V: Power input (4.5-8.4V DC)
- GND : Sol
- TX : CRSF Transmit (connect to RX on flight controller)
- Réception : CRSF Receive (connect to TX on flight controller)
- TX2/RX2 : Secondary UART port for advanced functionality.
5.2 Installation de l'antenne
Connect the two dual-band T-antennas to the IPEX-1 connectors on the receiver board. Position the antennas at a 90-degree angle to each other for optimal signal diversity. Use the provided heat-shrinkable tubes to secure and protect the antenna connections.
Cette image montre un angle view of the XR4 receiver board, highlighting the IPEX-1 antenna connectors and the soldering pads for power and CRSF communication.
6. Mode d'emploi
6.1 Binding Procedure (ExpressLRS)
The XR4 receiver comes pre-installed with ExpressLRS v3.5.1 firmware. To bind the receiver to your ExpressLRS transmitter module, follow these general steps:
- Ensure your transmitter module is running a compatible ExpressLRS firmware version.
- Power on the receiver. It will enter binding mode if it does not find a valid link. The LED on the receiver will typically flash rapidly.
- On your ExpressLRS transmitter, initiate the binding process. This is usually done via the Lua script or a dedicated bind button/menu option.
- Une fois la connexion établie, la LED du récepteur s'allumera en continu, indiquant une connexion réussie.
- If binding fails, ensure your transmitter and receiver have matching ExpressLRS firmware versions and binding phrases (if configured).
6.2 Operating Modes: Gemini and Xrossband (Gem-X)
The XR4 receiver supports various operating modes, leveraging its dual RF circuits:
- Gemini 2.4GHz: Uses two 2.4GHz antennas for dual-frequency operation within the 2.4GHz band.
- Gemini Sub-G 900MHz: Uses two 900MHz antennas for dual-frequency operation within the Sub-G 900MHz band.
- Xrossband (Gem-X): Utilizes one Sub-G 900MHz antenna and one 2.4GHz antenna for dual-band operation, providing enhanced reliability across different frequency ranges.
The specific mode is typically configured via the ExpressLRS Lua script on your transmitter or through the receiver's WebUI.
This diagram visually explains the different antenna configurations and packet transmission methods for Gemini 2.4GHz, Gemini Sub-G 900MHz, and Xrossband (Gem-X) dual-band modes.
7. Mises à jour du micrologiciel
The XR4 receiver features an integrated Wi-Fi module for convenient firmware updates and configuration. To update the firmware:
- Allumez le récepteur.
- Connect to the receiver's Wi-Fi hotspot from your computer or mobile device. The network name will typically be "ExpressLRS RX" followed by a unique identifier.
- Ouvrir un web navigateur et accédez à http://10.0.0.1.
- Utilisez le WebUI to flash new firmware or adjust settings. Refer to the official ExpressLRS documentation for detailed instructions on firmware flashing.
8. Entretien
The XR4 receiver requires minimal maintenance. Keep the device clean and free from dust and moisture. Regularly inspect antenna connections for damage. Ensure proper heat dissipation if operating in enclosed spaces.
9. Dépannage
- Pas de lien/Clignotement de la LED :
- Assurez-vous que le récepteur est correctement alimenté (4.5-8.4 V).
- Verify the transmitter module is powered on and transmitting.
- Check if the receiver is in binding mode (rapid LED flash). If not, re-initiate binding.
- Confirm that the transmitter and receiver are running compatible ExpressLRS firmware versions.
- Check for correct binding phrase if one is set.
- Mauvaise portée/qualité du signal :
- Inspect antennas for damage or improper connection.
- Ensure antennas are positioned optimally (e.g., 90 degrees to each other).
- Check for sources of interference near the receiver or antennas.
- Verify the selected operating mode (Gemini/Xrossband) is appropriate for your setup.
- Le destinataire ne répond pas :
- Check all wiring connections (power, ground, CRSF TX/RX).
- Ensure the flight controller or connected device is configured correctly for CRSF protocol.
- Attempt a firmware re-flash if the receiver is unresponsive.
10. Consignes de sécurité
- Always ensure correct power polarity before connecting the receiver. Incorrect wiring can cause permanent damage.
- Operate RC equipment responsibly and within legal limits.
- Tenez le récepteur à l'écart de l'eau, de l'humidité et des températures extrêmes.
- Do not attempt to modify the receiver's hardware beyond specified connection points.
- Assurer une ventilation adéquate pour éviter la surchauffe.
11. Garantie et assistance
Pour obtenir des informations sur la garantie et une assistance technique, veuillez consulter le site officiel de RADIOMASTER. webConsultez notre site web ou contactez votre revendeur agréé. Conservez votre preuve d'achat pour toute réclamation au titre de la garantie.
