RFD900, RFD900+ - New long range radio modem

Hi All,

I would like to introduce you to a new radio modem that we developed for very long range datalinks!


Some of the key features of the RFD900 are as follows:

  • Multi point and point to point link capability.
  • Long range >40km depending on antennas and GCS setup.
  • 2 x RP-SMA RF connectors, diversity switched.
  • 1 Watt (+30dBm) transmit power.
  • Transmit low pass filter.
  • > 20dB Low noise amplifier.
  • RX SAW filter.
  • Passive front end band pass filter.
  • Open source firmware / tools, field upgradeable, easy to configure.
  • Small (30 x 57 x 13 mm), light weight (14.5g).
  • Compatible with 3DR / Hope-RF radio modules.
  • License free use in Australia, Canada, USA, NZ.


These modems are designed to support long range applications, while being easy to use and affordable.  

These modems have been flying in various platforms and have demonstrated excellent performance in real applications. 

RFD900 modems are now available at: http://store.rfdesign.com.au

Support within APM planner and the radio configurator from Michael Oborne is already available.

It works seamlessly with APM planner, all radio Mavlink parameters are available.

Update, December 2014:  The RFD900+ with improved specifications is available now at:


Seppo Saario



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Hi Shameem,

Regarding the poor range on your setup, would you be able to email some pictures of the quad/antenna setup and the ground station antenna setup to info@rfdesign.com.au, or post them here?  - We may be able to offer some assistance with what you are seeing.

The antenna placement and ground reference for monopoles has a large effect on performance of the antennas.  Also, the RF noise level in band on the vehicle and ground station can significantly affect range too..

I have a couple of RFD900+ radios. If I get a 900X for my new airplane will it link with my 900+ ground station?

I tried to use the new 2.0 tool and it will not connect to my 900+ with 2.6 firmware. I have 1.6 tool on the same computer and it works. Is 2.0 tool for 900x only or am I doing something wrong?


Hi Seppo et al,

What is the status on regulatory compliance in Europe for RFD868x? Will this be pursued by RFDesigns at some point? Is there an eta for this? The documentation (particularly for the 868MHz version) is quite light but does state that "The modem is designed for system integrators who will integrate the modem into their own projects and product prototypes.  The user is responsible for compliance with local regulations for radio transmitters."...while listing the general compliance achieved for Oz/NZ and the US/Canada. It would be great to get the basic compliance confirmed for EU operation as well. 

If importing the modem to the EU as a consumer it seems to be hit and miss whether customs lets them through. My last order got returned to Australia by customs due to missing CE mark (and lack of statement of conformity / RTT&E, i think). 

I am supporting a project that looks at integrating a 868x into a commercial UAV which is sold in limited quantity - getting the end system compliance tested and certified is financially not feasible. Has anyone operating the units in Europe (or specifically Germany) had compliance successfully confirmed? Any practical tipps? 



Hi Seppo et all,

I have been using the RFD900 and 900+ for quite some time now. I m very happy with their performance. i had made a small change to the connection configuration of the modem with pixhawk. I am externally powering the RFD900 from before also. Now i have made a longer data cable for the interface between Pixhawk and the modem. After this particular change, it takes almost 2 full minutes for the initial connection to take place on the GCS. Previously, the connection would take a maximum of 20secs.

Nevertheless, the performance is still very good but the time taken for the initial connection is just too long. What could i possibly be doing wrong??

Thanks & Regards,


Does the RFD868x with FW 2.53 support single channel / non hopping mode? It does seem to accept the setting even though the config tool and docu says minimum number of channels is 5. 

Thanks + regards,


Dear Seppo,

My Rfd900 was working perfectly for 6 months now.Suddenly yesterday Stuck on boot loader mode. I tried uploading all the firmware available with all the available tools from rfdesign.com.au. Still nothing. Is it possible to send it to you and check what is happening? 

Kind Regards Dimitris

follow on about PPM use.

I have a system setup using the PPM over RFD900x to control a gimbal.

When the motor (electric heli) starts the gimbal usually rotates left and down. Looking at the PPM output from the radio it is outputting min on all channels (~1000us). If I turn off my RC transmitter I get output held for a couple of seconds then about 1500ms on chan 1 and 2 and min on chan 3...

I have tried to set the default (failsafe?) PPM value with the 

   AT&R Record default PPM stream for PPM output (vehicle side)

but I just get an "ERROR" Response... 

how do I set the default PPM (when there is no valid signal) to the vehicle ?

RT&R Record default PPM stream for PPM output (vehicle side)

When will the default be transmitted to the vehicle...


There will be a time lag of about a second before failsafe kicks in.

Please ensure you have V2.4 or later when using PPM as the recording had a bug previous to that.

Please ensure that you are connect via ftdi cable to the vehicle side when sending AT&R,

or to the ground side radio when sending RT&R.

You cannot set the default signal correctly until you have an active ppm stream going to your vehicle, otherwise there is no stream to record.

The default (recorded stream) will be sent once the vehicle side radio fails to see  a PPM stream for 50 ppm cycles. Cycle time varies between radios and stream length, but about 22ms is nominal , so roughly 1 second.

Did the RFD900 ever get FCC approved? If so, can you please provide the FCC ID?

Will the RFD work on the telem 2 output on the pixhawk 2.1? I have another sensor that needs to go into telem 1 because it needs the higher output. Or can I power the rfd900x with a bec?


I'm trying to use RFD868x or RFD868+ to transport a "unknown" framed synchronous protocol over about 10km distance point to point. The application is a closed system that doesn't implement flow control and damands a clear channel of 115kbps. As this is not MAVLink, we set the modems to rawdata and played with air data rate and max_window, but the goodput the application sees at the end never exceeds about 60-80%, even if distance is only a few meters (in this case, transmit power is set to 17dBm). 

Can anyone with experience in tuning RFD links with raw data / clear channel share any tipps on how to approach this or what settings to use? 

Thanks much in advance!



I've got a set of RFD900+ radios that I'm having trouble with. The local end is powered by USB through the jDrones RFD900 adapter (v1.1) from my laptop running the current version of Windows 10. The remote end is powered from a Pixhawk through the telemetry port. The radios will connect with each other as evidenced by the solid green light but 'no MAVLink hearbeats' are found before Mission Planner ( with Beta updates) times out leaving me disconnected. Both radios are running firmware 1.13. I'm on the correct COM port, baud is 57600. 

Attached is a screenshot of the radio settings.

What can I do to get these radios working? 

Many thanks in advance, Matt. 



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