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 All,

Out of the six teams who made it to the last stages of the UAV outback challenge 2012, three were using RFD900s for telemetry links! It was great to go to the competition and see the different airframes.

CompassUAV, Canberra UAV, and TGIF

TGIF (I am a member of) - was scrubbed due to a crash the day before the competition :(

Compass UAV made it through ground and flight scrutineering, but had autopilot problems through the flight.

Canberra UAV made it through, found joe!, and returned to the airfield!

Great flying teams :)

Great news...!

My RFD900 is coming. My skywalker UAV soon will be flying.

sorry about your crash and hate to ask but what happened?

Crash was due to a short runway, longer, bushy grass at the end and aircraft clipping the grass just as getting airborne.  It rapidly decelerated and swung around in the grass, snapping the tail boom.  We still needed a couple of hours of running through all the final test cases in the code and about 6 hours or so for the Epoxy to set for a tail repair.  Problem was this all happened early in the afternoon the day before the comp and ran out of time- !?  Hopefully there is a comp in a couple of years time ! :)

man its always little stuff you can never see coming anyway good luck at the next one

I've received mine a few days ago, and I must say I am also impressed with the build quality of the product...

I will be conducting a few methodical tests of distance/speed/RSSI in the next few weeks and I'm looking forward to sharing my results...

Hi, I have an issue. My local unit seems to wipe the firmware every time it's turned off. After powering up I load the firmware and it connects to the remote unit ok. Also, does anyone have any ideas on how to connect it to an APM1? I am powering the remote from a separate power source. I have looked and re-looked at the pin layout one the APM and the RFD but am none the wiser. Ta

The firmware can't be lost via a power failure, however reflashing the firmware will also clear the configuration. Some configuration registers only take effect after a reset, so you might be inadvertently putting something invalid or unexpected in there and the unit then comes up differently on next power-on.

The connection between an APM1 and the RFD900 should be the same as for the 3dr radio, using the bottom row of pins. Additionally, RX on the APM has to go to TX on the RFD900 and vice versa.

Sooo. Solved the problem with losing the FW. All you have to do is connect USB before you connect power (I'm using a separate power source).

As for the connection problem with the APM1: I have been able to connect to the APM, however I am not able to power the RFD900 from a separate source, as it requires a ground connection to the APM in order to work. I'm guessing that sharing grounds with a BEC is not exactly a good idea. Anyone care to enlighten me? 


I received the RFD900 modems and APM 2.5 months ago, and just recently noticed that the telemetry port is different. I plan on creating the connector myself, but after seeing the picture from the diydrones store, the red cable is at the middle for the radio side, and moved to the edge for the APM side. Aside from the red cable, is there any other cables that was moved?

Hello Hans,

That is correct in that a ground+tx+rx lines are required to the APM1 to make it work.

To run the RFD900 from an external supply, you can remove the jumper and connect GND from BEC to pin 2, and +5V from BEC to pin 4.

It will create a ground loop if you have only 1 BEC running the whole system, but in this case there is not much that you can do.  It has not caused any problems so far configures this way to date. 

The ideal configuration is to have a separate BEC running the RFD900 with GND and +5V coming from there.   The signal+GND lines to the APM would remain unchanged.

Hope it helps!


Hello Hans, 

Interested to hear how your testing has been going so far on the RFD900's !

If there's any more information that you need, let us know.



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