DBR4 Receiver User Manual

SPECIFICATIONS

• Item: DBR4 Dual Band Xross Gemini Express LRS Receiver
• Type: ISM 2.4G/ FCC 915M
• MCU: ESP32
• RF chip: Semtech LR1121 x 2
• Telemetry RF power: Max 100mw
• Antenna: 2x 2.4GHz wire & 2x 915MHz wire
• Frequency Range: 2.404 – 2.479 GHz / 903.5 – 926.9 MHz
• Maximum receive refresh rate: 500Hz (1000Hz coming soon in Express LRS V3.4)
• Minimum receiver refresh rate: 50Hz
• Working voltage: DC 4.5 – 8.4V
• Weight: Without antennas 2.70g / With antennas 5.30g
• Dimension: 27. 20*27. 20mm
• Firmware Version: Express LRS v3.3.2 pre-installed
• Bus interface: CRSF

INCLUDES

1 * DBR4 Dual band Xross Gemini ExpressLRS Receiver
2 * 2.4 GHz wire antenna
2 * 915 MHz wire antenna
1 * CRSF wire
4 * 4mm Red vibration dampeners
4 * 3mm Black vibration dampeners
1 * Manual card

DEFAULT FIRMWARE

RadioMaster DBR4 Dual band Xross Gemini Receiver
For more information, please visit the ELRS website: https://www.expresslrs.org/2.0/

CONFIGURATION

Open Betaflight Configurator, go to Ports tab and enable the corresponding UART as a Serial RX (e.g. UART2 as shown above). Save and Restart.

On the Configuration tab, click on Serial-based receiver on the Receiver panel, and select CRSF.

TRADITIONAL BINDING

Binding Phrase field must be uncommented in Device options on the RX.

1. Power OFF your transmitter/radio.
2. Plug in and unplug your receiver 3 times.
3. Make sure the LED is doing a quick double blink, which indicates the receiver is in bind mode.
4. Power ON your transmitter/radio and use the [BIND] button on the ExpressLRS Lua script, which sends out a binding pulse.
5. If the receiver has a solid light, it’s bound!

Documents / Resources

RADIOMASTER DBR4_1.0 Boxer Radio Controller [pdf] User Manual DBR4_1.0, RP3, DBR4_1.0 Boxer Radio Controller, DBR4_1.0, Boxer Radio Controller, Radio Controller, Controller

References

• User Manual