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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  • Do anyone know if it is possible to make the RFD868+ modems output a continuous unmodulated carrier? I would like to measure and verify the output power.

    • Hi Ikaros,

      It is possible to setup a custom version of firmware to do that -


      is a version of firmware that we set to transmit 2 sec pulses at 922MHz for testing for one specific application.

      To set the RFD868 modems to do a similar thing, the frequency needs to be set to 868-869MHz or so.

      Hope it helps!


      Tools and firmware for the Si1000 - Si102x/3x. Contribute to RFDesign/SiK development by creating an account on GitHub.
      • Hi Seppo,

        Ok thanks a lot!

  • Hi.


    I have been doing some range testing and I would like to ask you about the recorded data.

    Here is a typical plot from one of the tests:


    I don’t know why 3 of the variables suddenly logs the same value, have anyone else had the same experience?

    • Hi Ikaros,

      I have not seen that before...  The only thing I can think of is that the modems have lost lock for a moment?..  The local noise level is fluctuating a lot to very high levels..  ~92 or so, peak !...  What kind of area is the testing done in?,  countryside, or urban areas?...   It looks to be a very RF noisy area, some times if there are mobile phone base stations nearby, they can increase the noise floor quite a lot.


      • Hi Seppo,

        Ok, the testing was done over water close to a village at 7 km range. Will update here if the problem appears again.

  • Hi Patrick,

    It looks like some emails have been lost at our server end?? - Could you send your email and order info via message here please and I will look into it for you.


  • Patrick the Chinese are the worst about this, I wouldn't have expected this out of the Aussies,

     Call 214-702-6286 HeliBatics.com and get hold of David, sometimes his wife answers the phone, she is Vietnamese and a very nice person, her english is a little rough but you will be able to understand her, just ask for David and he will fix you up with anything that the RFD900+ needs. he is well informed about 900.

    HeliBatics.com is out of Texas

    Check out this


  • Why is the 900+ not connecting or dropping signal ?

  • I just tried to separate my RFD868+ modems by 20 meters and connected the power. They didn’t work. First time I plugged in the power the connection was constantly dropping I then restarted again and the connection was perfect. Repowered again still perfect. The fourth time constantly dropping.


    I then flashed the older firmware v1.12. No improvement, first time everything was perfect, no lost packages, repowered and the connection was constantly dropping.


    Right now I am out of ideas, may I ask again, does anyone use the RFD868+ without problems?

    I would love to make them work so we can test them in the air as soon as possible, maybe I am doing some small mistake somewhere.


    Best Regards

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