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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    • Here's a revision to my enclosure design. This one is intended to mount to booms(tubes), masts, etc. Will custom make any clamp up to 30mm for you (ad shows 20mm boom):

      RFD900 Enclosure

    • Can you print them out for me for a Price ?

      I don't have a laser printer.

  • i had a mishap crash and the RFD900+ on my copter got hit and one of the antenna connections broke off....is there any way to have it fixed?  am so mad....

  • Hi Seppo

    I bought rfd900u for plane and rfd900 for GCS. I installed rfd900u on fx-61 plane and mount the dipole antenna on the tail (picture attached).

    I'm stuck try to connect rfd 900 and rfd900u. I checked the firmware of rfd900 and it installed with version 1.9 sik. But I try to connect rfd900 using jumper based on datasheet to usb to check the firmware using rfdtools but I have no luck, rfdtools cannot read settings on rfd900u.

    Is there a way to check firmware on rfd900u via usb cable, because I assume maybe the cause connection problem is different firmware between rfd900u and rfd900.

    Or is there other explanations why I cant connect rfd900 to rfd900u?


  • Hi, Seppo,

         I can connect my RFD900+ to RFD900+ with FW 1.9 with no problem as long as the green light on the unit stay solid. If I use config tool, then green light will start blinking, even after I finish with config tool, which make connection impossible. The only way to fix that is restart my computer. I tried to unplug unit from computer, no work. I'm trying to find a way to fix that without restart my computer. I'm thinking about that probably because when I use config tool, it puts unit in to "config mode", therefore, it doesn't let me connect, just like solid red light is bootload mode.

         Also, config tool 1.6 can not make unit go boot load mode. But I managed to use Mission planner to get in bootload mode. Hope you can fix that.


  • This reply was deleted.
    • Hi Jeremy,

      The 3dr modems have ECC enabled by default.  I found that the 900+ will not connect with either the RFD900 or 3dr modems if ECC in enabled, no matter what version the firmware.  Here is Seppo's reply on that:

      Hi Don,

      There has been a bit of work back/forth over time with ECC.  The problem has been limited code space available on units with features that have been added.  http://files.rfdesign.com.au/firmware/

      Has the current and a few good historical versions.  RFD900p V1.9

      would be worth checking with compatibility with 3DR modems and older firmware.

      My experience with ECC has been that some times it has trouble loading parameters in mission planner, and the extra correction capability has not really been needed for most applications.  As a result, it hasn't had much of a focus over time.  In addition, ECC doubles the bandwidth requirements for the link, reducing the telemetry rates available.

      Modem firmware development has slowed a little, the next features needing to be tested are AES encryption..



      Firmware | RFDesign Files
      Here you will find Supporting files, Binaries and Tools to use our products
      • This reply was deleted.
        • Jeremy,

          You have to disable ECC on both modems. 

          The NetIDs have to be the same, but NodeID is for when one radio (say the aircraft's) is communicating with more than one other radio (say multiple ground stations).  In which case, one has to be the master (node 0) and the others slaves (not node 0).  But, you also have to running the Multipoint SIK firmware.  I think you can change NodeID only if you are running the Multipoint SIK (I never have).

          Setup instructions are pretty sketchy and "facts" you find in the forums are largely anecdotal.  


  • Hello,

    Seppo wrote in RCGroups this:

    "the new 900MHz modem (RFD901?), may be able to do PPM in and PPM out directly from the modem. So, not sure on the best solution here. Any thoughts on a good way to go about long range RC would be well received."

    Someone knows about or has tested this feature?

This reply was deleted.


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