Dual-band ExpressLRS receivers like the Radiomaster DBR4 are quickly becoming favorites among FPV pilots, and for good reason. By combining the 2.4 GHz and 915 MHz bands in a single receiver, the producer offers the best of both worlds: 2.4 GHz provides ultra-low latency and stable performance for racing and freestyle. At the same time, 915 MHz extends range and penetration through obstacles, making it ideal for long-range flights.
Another key performance factor is the number of antennas on the receiver—having two or even four antennas can significantly improve signal reception and diversity, reducing dropouts and ensuring a more reliable link in challenging environments. This review will look in-depth at the DBR4 Xross Dual-Band Gemini ELRS receiver and determine who is pro or against.
One of the standout features of the Radiomaster DBR4 receiver is its four-antenna design—two dedicated to 2.4 GHz and two to 915 MHz. This setup ensures a more reliable connection across various flight conditions, from indoor spaces to long-range outdoor adventures. It’s strongly recommended to use antennas explicitly tuned for each frequency rather than universal antennas for optimal performance. Tuned antennas maximize signal efficiency on their respective bands, giving you stronger range, cleaner link quality, and more consistent telemetry, which is crucial when pushing your FPV flights to the limit.
Radiomaster DBR4 review
Disclosure: I received this dual-band ELRS receiver from RadioMaster to test and do an in-depth review. Although the RX was offered for free, all opinions in this article remain my own, with no influence from my partner. I can’t guarantee you will get the same radio.
Along with their latest release, the TX15, RadioMaster also sent me the DBR4, allowing me to test the radio on both ELRS bands. The radio receiver is packed in a basic antistatic bag with included antennas, CRSF wires, and two sets of mounting rubber grommets (4mm and 3mm).
The Radiomaster DBR4 stands out with its unique design, featuring four thin wire antennas extending from its square board. These antennas, two for 2.4 GHz and two for 900 MHz, fan outward in different directions to maximize reception and minimize blind spots. The look is almost organic—resembling the Sentinels from The Matrix, with their menacing tangle of mechanical tentacles searching for prey. Fortunately, unlike those ship-destroying machines, the DBR4’s “tails” aren’t built for destruction but for reliable dual-band connectivity, ensuring rock-solid control links even in demanding FPV environments.
Measuring 27×27 mm, this receiver is noticeably larger than most other ELRS options on the market, even compared to the compact GEMINI series. While the increased footprint may limit its use in very tight builds, the additional space allows improved component layout and better heat dissipation. It has a 20×20 mm mounting pattern, supported by many frame types, including the popular FlyFish Volador VD6, which I use as a test platform due to its easy disassembly and dual mounting stacks that can accommodate various hardware.
The board features two Semtech LR1121 third-generation ultra-low power LoRa transceivers. Currently, it supports up to a 500 Hz refresh rate, but 1000 Hz will become available through future firmware upgrades. Like most ELRS RX modules, the Radiomaster DBR4 also has an onboard ESP32 MCU, a single 2.4 GHz Wi-Fi and Bluetooth combo chip designed using TSMC’s low-power 40 nm technology. The RX can be powered from 4.5 V to 8.4 V; ideally, you should solder it to the FC’s 5 V BEC.
Gemini and XrossBand (GEMX) antennas
The photo below shows the Gemini and Xrossband (GEMX) antennas side by side. While both are designed for ExpressLRS receivers, the GEMX antennas stand out with their dual-band matching, optimized for 2.4 GHz and 915 MHz performance. As mentioned, this setup helps reduce blind spots and ensures a stronger, more reliable signal during flights. The ELRS GEMINI operates either over 2.4 GHz or 915 MHz (Sub-GHz) on both antennas.
Radiomaster DBR4: Technical specifications
| Bands | ISM 2.4GHz FCC 915Mhz |
| Antennas | 2x 2.4Ghz wires 2x 915Mhz wires |
| RF chips | 2 x Semtech LR1121 |
| MCU | ESP32 |
| Telemetry RF power | Max 100mW |
| Receive refresh rate | Minim: 50Hz Maxim: 500Hz Upcoming: 1000Hz in ELRS 3.4 |
| Bus interface | CRSF |
| Working voltage | DC 4.5-8.4V |
| Dimensions | 27x27mm |
| Mounting pattern | 20x20mm |
| Weight | 5.5grams (including antennas) |
Pricing and availability
This Dual-Band Xross Gemini ELRS radio receiver can be purchased directly from the manufacturer’s website for $29.99. For FPV pilots looking for a reliable, dual-band setup, this price offers an affordable entry into high-performance ELRS connectivity, making it a strong option for both racing and long-range flying.
Radiomaster DBR4: Who’s for and who’s not?
Although the DBR4 Gemini Xrossband receiver has four antennas, it currently uses only two at a time—one for 2.4 GHz and one for 915 MHz. This setup allows the system to switch seamlessly between bands while providing improved signal reliability and redundancy, but all four antennas are not used simultaneously.
Considering the extra weight and larger size, the slight performance increase is not a good trade-off, so I will continue using dual-antenna Gemini and dual-band receivers depending on the build. On the other hand, if you need maximum antenna efficiency and performance for a long-range VTOL, this ELRS receiver is probably the best choice. Remember, to get the most out of it, you will need a fully compatible radio transmitter.
