RadioMaster DBR4 Dual Band Xross Gemini ExpressLRS Receiver

The Gemini design runs two independent RF channels simultaneously on 2.4GHz and 900MHz. This provides automatic frequency redundancy; if one band experiences interference or signal degradation, the other maintains the control link, significantly boosting reliability in congested environments or on long-range flights.

The DBR4 supports a maximum refresh rate of 500Hz out-of-the-box with its pre-installed v3.3.2 firmware. To achieve 1000Hz, you must update the receiver and your compatible ExpressLRS transmitter module to firmware version 3.4 or later, which unlocks the higher packet rate for ultra-low latency control.

Yes. The DBR4 has a wide operating voltage range of 4.5V to 8.4V, which covers the nominal voltage of a 2S LiPo (7.4V). You can connect it directly to a 2S battery's balance lead or main power leads via a suitable connector, eliminating the need for a separate 5V BEC in many builds.

For optimal diversity, position the two 2.4GHz antennas and the two 900MHz antennas perpendicular to each other (e.g., one vertical, one horizontal). Try to separate antennas of the same band by at least a few centimeters and keep them away from carbon fiber or battery packs to minimize signal blockage and ensure robust reception from all angles.