RadioMaster DBR4 Dual-Band Xross Gemini ExpressLRS Receiver

The RadioMaster DBR4 is an advanced ExpressLRS receiver that leverages dual-band Xross Gemini technology to deliver a highly resilient control link. By operating concurrently on both the 2.4GHz and 900MHz bands, it maintains robust control and telemetry for long-range FPV rigs, heavy-lift cinelifters, and macro-drones flying in saturated RF environments.

Key features

• Transmits and receives simultaneously across two distinct frequency bands to bypass local signal interference.

• True hardware diversity manages dedicated antennas for 2.4GHz and 868/915MHz, allowing optimal spatial placement away from carbon fibre frames.

• Eliminates the latency of traditional band-switching fail-safes by keeping two active RF links locked at all times.
  
  

Specifications

• Manufacturer: RadioMaster

• Model: DBR4

• Supported firmware: ExpressLRS (requires v3.3 or newer for Gemini support)

• Operating frequencies: 2.4GHz & 868/915MHz

• Frequency range: 2.404-2.479 GHz / 903.5-926.9 MHz

• MCU / RF chip: ESP32 / 2x Semtech LR1121

• Telemetry power: 2x 100mW max

• Refresh rate: 50-500Hz

• Bus interface: CRSF

• Working voltage: 4.5-8.4 V DC

• Antennas: 4 discrete wire antennas (2x 2.4GHz, 2x 900MHz)

• Mounting: 20 x 20 mm holes, vibration dampeners included

• Dimensions: 27.2 x 27.2 mm

• Weight: 2.7 g without antennas, 5.3 g with antennas

To fully utilise the Xross Gemini concurrent dual-band capabilities, this receiver must be paired with a compatible dual-band ExpressLRS transmitter module.