RadioMaster DBR4 Gemini Xrossband ExpressLRS Receiver
Technical Highlights
Dual-Band Gemini Xrossband Reception
The DBR4 is an ExpressLRS receiver designed for 2.4GHz and sub-GHz operation. The FCC-version frequency ranges listed by RadioMaster are 2.404–2.479GHz and 903.5–926.9MHz.
Four Separate Antennas
The receiver uses two 2.4GHz wire antennas and two 900MHz wire antennas. The supplied product photographs show four antenna connections on the DBR4 board.
CRSF Interface and Compact Mounting
A CRSF bus interface connects the receiver to the intended control system. The 27.20 × 27.20mm board provides a 20 × 20mm mounting-hole pattern.
Receiver Telemetry Power
RadioMaster's specification table lists maximum telemetry RF power of 100mW. Its feature list separately states a maximum of 2 × 100mW; neither figure is an FPV video-transmitter rating.
RF and Interface Specifications
| Model | DBR4 Gemini Xrossband ExpressLRS Receiver |
|---|---|
| Receiver Protocol | ExpressLRS Gemini Xrossband (GemX) |
| Regulatory Version | FCC; manufacturer specification identifies ISM_2.4 and FCC_915 |
| Frequency Range | 2.404–2.479GHz / 903.5–926.9MHz |
| Telemetry RF Power | Maximum 100mW in the manufacturer specification table; the feature list separately states maximum 2 × 100mW |
| Bus Interface | CRSF |
| Antenna Configuration | Two 2.4GHz wire antennas and two 900MHz wire antennas |
| MCU | ESP32 |
| RF Chips | Two Semtech LR1121 transceivers |
Electrical and Physical Specifications
| Working Voltage | 4.5–8.4V DC |
|---|---|
| Board Dimensions | 27.20 × 27.20mm |
| Mounting Holes | 20 × 20mm pattern |
| Weight Without Antennas | 2.70g |
| Weight With Antennas | 5.30g |
Selection and Installation Notes
Select the correct regional frequency version and confirm the transmitter's ExpressLRS Gemini Xrossband mode before installation.
Use the 2.4GHz and 900MHz antennas at their corresponding board connections; the antenna groups are not interchangeable by label.
Supply 4.5–8.4V DC and use the CRSF interface for the intended control-system connection.
The DBR4 is an RC receiver. Its telemetry-power specification must not be presented as FPV video output power.
FAQ
Is the DBR4 only a 2.4GHz receiver?
No. The FCC-version specification lists both 2.404–2.479GHz and 903.5–926.9MHz frequency ranges.
Is the DBR4 an FPV video transmitter?
No. It is an ExpressLRS RC receiver with a CRSF bus interface. Its RF power figure refers to telemetry, not video transmission.
How many antennas does the DBR4 use?
RadioMaster specifies four separate wire antennas: two for 2.4GHz and two for 900MHz.
Should the telemetry figures be added together as 200mW?
No combined 200mW rating should be inferred. RadioMaster's specification table states a 100mW maximum, while its feature list describes up to 2 × 100mW. Confirm the intended per-chain interpretation with RadioMaster when it matters to a project.
B2B Procurement FAQ
What should be specified in a DBR4 inquiry?
Specify RadioMaster DBR4, the required regional frequency version, quantity, CRSF interface and intended Gemini Xrossband transmitter setup.
Can the FCC frequency specification be used for every region?
No. The frequency ranges on this page are the FCC-version values listed by RadioMaster. Confirm the required regional version and its applicable frequency configuration before ordering.
Are MOQ, price and lead time fixed?
Minimum order quantity, price, availability and lead time must be confirmed during quotation.
Leave Your Message
Products categories
-
RadioMaster DBR4 Gemini Xrossband Expres
-
RadioMaster Bandit BR3 ExpressLRS Receiv
-
RadioMaster Bandit BR1 ExpressLRS Receiv
-
MATEKSYS R24-P6V ExpressLRS PWM Vario Re
-
MATEKSYS mR24-30 2.4GHz mLRS Receiver
-
MATEKSYS ELRS-R24-D 2.4GHz Receiver
-
HPXGRC 2.4GHz ExpressLRS Micro Receiver
-
RUSHFPV TANK Ultimate Mini 5.8GHz VTX
-
HGLRC Zeus VTX 2.5W 5.8GHz Analog Video
-
HGLRC Zeus Nano 5.8GHz 350mW Analog VTX