RadioMaster DBR4 Dual-Band Xross Gemini ExpressLRS Receiver

The DBR4 receiver is the perfect partner for the RadioMaster Nomad module. The DBR4 is an advanced dual-frequency, dual-channel Gemini receiver that provides seamless compatibility with the Nomad module. Designed for ultimate performance, the DBR4 features two dual-frequency sections that can simultaneously receive both 2.4 GHz and 900 MHz signals. This innovative design allows for simultaneous processing of two data streams, providing exceptional immunity to interference. With the DBR4, you can be sure that your signal will remain strong and reliable, giving you the confidence to push your limits and explore new possibilities. Enhance your RC experience with the unmatched connectivity and performance of the DBR4 receiver.

Features:

• Telemetry RF power: max. 2 × 100 mW;
• Experience an unparalleled experience with the dual-frequency ELRS Gemini Xrossband;
• ExpressLRS Gemini 2.4 GHz;
• ExpressLRS Gemini 868/900 MHz;
• 4 separate antennas for optimal placement;
• Mounting holes: 20 × 20 mm;
• Supports Xrossband GemX system.

Specification:

• Item: DBR4 Gemini Xrossband ExpressLRS receiver;
• Type: ISM_2.4, FCC_915;
• Controller (MCU): ESP32;
• RF chip: Semtech LR1121 × 2;
• Telemetry RF power: Max. 100 mW;
• Antennas: 2 × 2.4 GHz, 2 × 900 MHz;
• Frequency range: 2.404 – 2.479 GHz / 903.5 – 926.9 MHz;
• Maximum reception refresh rate: 500 Hz (1000 Hz – coming soon with ExpressLRS V3.4);
• Minimum receiver refresh rate: 50 Hz;
• Operating voltage: DC 4.5 – 8.4 V;
• Weight: Without antennas – 2.70 g / With antennas – 5.30 g;
• Dimensions: 27.20 × 27.20 mm;
• Software version: ExpressLRS v3.3.2 (pre-installed);
• Interface: CRSF.

New packet transmission frequencies:

• Sub-GHz 250Hz (-111 dBm):
Faster Transmission: Achieve higher packet refresh rates with improved Sub-GHz performance.

• Sub-GHz 200Hz Full (-111 dBm):
Optimized for Mavlink users: twice the data rate of the existing 900 MHz SX1276 device, specially adapted for the Mavlink protocol - for stronger connections and less interference.

• Dual frequency X150Hz (-112 dBm):
Gemini Mode: Simultaneous transmission of Sub-GHz and 2.4GHz signals ensures highly reliable communication and reduced interference with a 150Hz packet transmission frequency.

• Dual frequency X100Hz Full (-112 dBm):
Advanced Gemini Mode: Same dual-frequency benefits with 100Hz packet rate and full 16-channel resolution for reliable communication even in challenging conditions.

New K modes:

• DK500 (will be available with ExpressLRS V3.5):
Designed from the ground up for speed and RC reliability enthusiasts. K-modes are a next-generation FSK modulation with built-in packet recovery (Forward Error Correction). Similar to the FLRC D500, the DK500 sends repeated packets to reduce the chance of losing connection during intense racing. When used with the Gemini transmitter and receiver, it provides unmatched RC reliability.

• K1000 Full SubGHz (will be available with ExpressLRS V3.5):
Yes, you read that right – 1000Hz in the 868/900 MHz frequency range! This mode is designed for maximum data transfer rates with MAVLink, but during testing it proved effective even in long-range conditions.

Package:

1× DBR4 Gemini Xrossband ExpressLRS receiver;
2× 2.4 GHz wired antennas;
2× 900 MHz wire antennas;
1× CRSF connection cable;
4× 4 mm red anti-vibration shock absorbers;
4× 3 mm black anti-vibration shock absorbers;
1× Instruction card.