Quick Answer
The RFD900x operates on 902-928 MHz and is designed for the US and rest of world, while the RFD868x operates on 865-870 MHz and is configured for legal use within the EU. If you are flying in Europe, the RFD868x is your choice. For the US, Australia, or most other regions, the RFD900x is the correct option. Both are MAVLink serial telemetry radios made by RFdesign, an Australian company, and both are NDAA compliant.
What Are These Radios?
RFdesign telemetry modems let your drone talk to your ground station over long distances. They carry MAVLink telemetry data between your Pixhawk flight controller and Mission Planner or QGroundControl. These are not video transmitters. Your 5.8 GHz system handles video. The 868/900 MHz radios handle the data link: GPS position, vehicle status, command-and-control messages.
Both the RFD900x and RFD868x use the same SiK firmware platform and share most features. The real difference comes down to the radio frequency band they operate on, which determines where you can legally use them and how they perform in different environments.
Head-to-Head Comparison
| Feature | RFD900x | RFD868x |
|---|---|---|
| Frequency Band | 902-928 MHz | 865-870 MHz |
| Region | US, Australia, ROW | EU |
| FCC Approved Variant | Yes | N/A |
| Protocol | MAVLink | MAVLink |
| Firmware | SiK | SiK |
| NDAA Compliant | Yes | Yes |
| ArduPilot Compatible | Yes | Yes |
| PX4 Compatible | Yes | Yes |
| Typical Range | Up to 15+ km ( LOS ) | Up to 15+ km ( LOS ) |
Which One Should You Buy?
Flying in the EU
The choice is straightforward. European regulations restrict unlicensed use of 900 MHz, so the RFD868x is the legal option. It operates within the 865-870 MHz band allocated for licence-exempt short-range devices. The EU v2 variant is the latest revision with updated firmware pre-installed.
Flying in the US
The US has FCC regulations around 900 MHz spread-spectrum devices. Use the FCC-approved RFD900x to stay compliant. The standard RFD900x is also available for general long-range use outside regulated environments.
Flying in Australia or ROW
The standard RFD900x is the go-to. RFdesign is an Australian company, and these radios were originally developed with Australian conditions in mind. They work well across most of Asia, Africa, and South America too.
What About the UX Models?
RFdesign also makes updated versions: the RFD868ux and RFD900ux. These "ux" models offer improved RF performance, lower power consumption, and a smaller form factor. The RFD900ux even carries DoD Blue UAS approval under NDAA Section 848. We cover the full comparison in our RFdesign module comparison guide.
For most builders, the standard x-series is still the best value. The ux-series is worth considering if you need the latest hardware or specific compliance certifications.
Performance in Practice
In real-world conditions, both radios deliver similar range when used with appropriate antennas. Line-of-sight range depends on antenna gain, transmit power, and local interference. Expect reliable telemetry at 10-15 km with stock dipole antennas, and well beyond that with directional antennas on the ground station.
The 868 MHz band (EU) is generally less crowded than 900 MHz (US), which can mean slightly cleaner spectrum in built-up areas. The 900 MHz band has slightly better propagation characteristics at the same power level, which can translate to marginally better range in open terrain.
Frequently Asked Questions
Can I use an RFD900x in the EU?
Technically yes, but operating on 900 MHz in the EU may not comply with local radio regulations. The RFD868x exists specifically to operate within the EU licence-exempt band. Stick with the correct radio for your region.
Do I need two radios?
Yes. One radio mounts on your drone and connects to the Pixhawk flight controller. The other connects to your ground station PC via USB. They come pre-configured as a paired set out of the box. Browse the full RFdesign range for individual modems and bundles.
Are these compatible with iNav or Betaflight?
RFdesign radios work with MAVLink-based firmware. They are fully compatible with ArduPilot and PX4. For a closer look at firmware options, see our long-range communication guide.