RadioMaster DBR4 User Manual

2.4
GHZ
900M
LR1121
SPECIFICATIONS
•Item: DBR4 Dual Band Xross Gemini ExpressLRS 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 ExpressLRS 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: ExpressLRS 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/
TOP
2.4G
900M
2.4G
LR1121
LR1121
DBR4 Receiver User Manual
BOTTOM
27.2 mm
ESP32
150
mm
LR1121
CONFIGURATION
Identifier Configuration/MSP
USB VCP 115200
UART1 115200
UART2 115200
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
Receiver
Serial (via UART) Receiver Mode
•
The UART for the rec eiver must be s et to 'Serial Rx' (in the Ports tab)
• Selec t the correc t data format from the drop-down, below:
CRSF
Serial Receiver Provider
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!
900
M
Serial RX
.