FOXEER ELRS 915/868MHz Diversity Receiver User Manual

1. Introduction

The FOXEER ELRS 915/868MHz Diversity Receiver is a high-performance receiver designed for long-range FPV (First Person View) drone applications. Utilizing the ExpressLRS (ELRS) open-source radio link, it offers robust signal reliability and advanced features such as telemetry and high refresh rates. This manual provides essential information for the proper installation, operation, and maintenance of your receiver.

Figure 1: FOXEER ELRS 915/868MHz Diversity Receiver (Front and Back)

2. Specifications

Below are the detailed specifications for the FOXEER ELRS Diversity Receiver:

Figure 2: Detailed Specifications and Features

3. Package Contents

The package includes the following items:

• 1x FOXEER ELRS 915/868MHz Diversity Receiver
• 2x T-Antennas
• 1x Real Shrink Tube
• 1x Connection Cable

Figure 3: Included Components

4. Setup

4.1 Wiring Diagram

Connect the receiver to your flight controller (FC) according to the following diagram. Ensure correct polarity for power connections (5V and GND) and proper UART connections for data (TX and RX).

Figure 4: Receiver Wiring to Flight Controller

• 5V: Connect to a 5V power pad on your FC.
• GND: Connect to a Ground pad on your FC.
• TX (Receiver): Connect to an RX pad on your FC (e.g., RX2, RX3, etc.).
• RX (Receiver): Connect to a TX pad on your FC (e.g., TX2, TX3, etc.).

4.2 Antenna Installation

Carefully connect the two T-antennas to the IPEX connectors on the receiver module. Ensure they are securely attached. Position the antennas away from carbon fiber frames and other electronics for optimal signal reception. The diversity feature utilizes both antennas for improved signal quality.

4.3 Firmware Flashing and Binding

The receiver comes with ELRS FW V3.2.0 pre-installed. For initial setup or firmware updates, you will need to flash the receiver with compatible ExpressLRS firmware. This typically involves:

1. Connecting the receiver to your computer via a UART-to-USB adapter (not included) or using passthrough flashing via your flight controller.
2. Using the ExpressLRS Configurator software to select the correct target (e.g., FOXEER RX1000_ELRS_900) and desired firmware version.
3. Flashing the firmware.
4. Binding the receiver to your ELRS transmitter module. This usually involves powering the receiver on and off three times rapidly, or using a bind phrase configured in the ELRS firmware. Refer to the official ExpressLRS documentation for detailed binding procedures.

The flash frequency can be set between 25-200Hz, allowing for customization based on your flight controller's capabilities and desired responsiveness.

5. Operating Instructions

Once the receiver is correctly wired, flashed, and bound to your transmitter, it will establish a radio link. The CRSF (Crossfire) protocol is used for communication between the receiver and the flight controller.

• Power On: Power on your FPV drone. The receiver's LED indicator will show its status (e.g., solid for bound, flashing for binding mode).
• Telemetry: The receiver supports telemetry with an RF power of up to 50mW Max. This allows your flight controller to send data back to your transmitter, such as battery voltage, RSSI (Received Signal Strength Indicator), and link quality. Ensure telemetry is enabled in your flight controller's configuration (e.g., Betaflight, ArduPilot).
• Refresh Rate: The receiver supports a high refresh rate of up to 200Hz, providing low latency control. The actual refresh rate will depend on your transmitter module's settings and the overall ELRS link configuration.

6. User Tips

• Antenna Placement: Always ensure your antennas are mounted in a 'V' shape or at 90-degree angles to each other for optimal diversity performance and signal reception. Avoid placing them directly against carbon fiber.
• Firmware Updates: Regularly check the official ExpressLRS project for the latest firmware updates. Updates often bring performance improvements, new features, and bug fixes.
• Bind Phrase: Using a unique bind phrase is highly recommended for security and convenience, as it eliminates the need for physical binding button presses.
• Power Supply: Ensure a stable 5V power supply to the receiver. Unstable power can lead to unexpected disconnections or poor performance.

7. Maintenance

The FOXEER ELRS Diversity Receiver is designed for durability, but proper care can extend its lifespan:

• Physical Inspection: Periodically check the receiver and antenna connections for any signs of damage, loose wires, or corrosion.
• Cleaning: Keep the receiver free from dust, dirt, and moisture. Use a soft, dry brush or compressed air for cleaning. Avoid using liquids.
• Heat Management: While the receiver is small, ensure it has adequate airflow, especially if mounted in an enclosed space, to prevent overheating.
• Antenna Protection: Protect the antennas from physical impact. The included shrink tube can help secure and protect the antenna connections.

8. Troubleshooting

If you encounter issues with your receiver, consider the following troubleshooting steps:

9. Warranty and Support

FOXEER products are manufactured to high standards. For warranty claims or technical support, please contact your retailer or visit the official FOXEER website. Keep your proof of purchase for any warranty-related inquiries.

For the latest ExpressLRS firmware and community support, please refer to the official ExpressLRS project documentation and forums.