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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  • @ Seppo

    I have noticed that the antenna's you sell are not listed a vertically polarized or horizontally polarized on the stores web page. I think that would be helpful.. And on the same subject.... is it important that a vertically polarized antenna be vertical or only that it is the same as the one on the ground radio? I accidentally installed that long thin horizontal one vertically on my planes rudder. Couldn't I simply do the same with one on the ground or is there more to it than that? Thanks.

    • Developer
      @ richard. .. if the long axis of the antenna is mounted vertically, like top-to-bottom on the tail fin of your aircraft then it IS vertically polarized. On the ground, you thus need one of the ground antenna to also be vertical. That is the usual method. If you are using the pair of stick on flat antennas then the other antenna should have its long axis out on one wing and parallel to the ground.... it is the horizontally polarized one, and you need a horizontal antenna on the ground for that....
      • Okay cool thanks that's about what I figured but wasn't sure.

  • Just a quick update on things that we're up to !

    We have just added some more antennas to the online store - 6dBi outdoor, omnidirectional antennas which are good for more permanent, rugged installations.   Some more 900MHz antennas are coming soon.  

    RFD Flex 2 Antennas are coming with cable options for 500mm and 1m for mounting on vertical stabilisers, to give vertical polarisation, to complement the typical Flex1 install.

    The RFD900u is coming back into stock soon, we have some units incoming this week (Mid Sept, 2014).  In addition, an updated version of the RFD900u V1.2 is being built.  The key difference is the ability to surface mount the modem onto another PCB via castellations (vias at the edge of the board).  The DF13 connector will remain the same.

    RFD900u V1.2 will be FCC modular and IC approved by the end of the year :)

    Hardware accelerated encryption has been demonstrated, but needs to be integrated into the main firmware tree - this will be a good step in making sure that the link to the UAV remains secure.

    I shall keep you posted on how things are going !


    • Hi All!,

      Luke and I were able to go to the UAV outback challenge at Kingaroy on Wednesday, the first day of the search and rescue challenge.


      There were 15 teams competing on the day and 14 of them were using the RFD900 for their datalink ! - It was amazing to see the installations and get great feedback from the teams - thankyou!

      On Thursday, 25/9/14, two teams completed the outback challenge, for the first time ever !, tomorrow there are 6 more teams running -- good luck all !!  

      UAV Challenge
      UAV Challenge, Kingaroy, QLD. 5.2K likes. The UAV Challenge is an international unmanned aircraft competition based in the Australian Outback.
  • Hi Seppo, fantastic work on the RFD900. My name is Horace and I am part of a Jamaican UAV dev team working on an ambitious program which involves the use of UAVs in anti IUU(Illegal, Unregulated and Unreported) fishing. We are currently working with the techpod airframe as the airframe of choice for trials to see just how effective these systems can be.

    The area we want to cover is huge: 2/3 the size of the island of Jamaica in an area in the center of the Caribbean basin just south of Jamaica called the Pedro banks. The target area for surveillance in the Pedro banks is Northwest Ridge , a relatively shallow bank located on the southwestern portion of the Pedro banks, this is where most of the illegal fishing takes place. This bank is approx. 110km from Middle Cay which is a small island where fishermen and the coast guard is based. The closest 'island ' to northwest ridge is southwest rock located 63km away. Southwest rock is literally a rock with a mast on it...

    My plans:

    We need to be able to reach northwest ridge from middle cay, my plan is to mount a repeater on southwest rock that would amplify the signal being sent by the RFD900 radio located at base station on middl cay. This would allow diect UAV flights from middle cay to northwest Ridge, maintaining radio connection along the way.

    How could I set up such a network?
    • Hi Horace,

      That certainly sounds like an interesting application..

      The only practical way of setting up a repeater network as you describe would be with 2 modems back to back at southwest rock - each modem there would have it's own network ID.

      The aircraft could connect to southwest rock always.

      The southwest rock repeater would connect to the GCS with a high gain yagi.

      There are a lot of things that could be done with multipoint and relaying data, but, that has not been implemented yet.

      • Thanks for the info Seppo.

        One concern I have about using a yagi on the repeater rather than a high gain dipole is that the aircraft would lose gain if it is not directly aligned in the transmission beam of the repeater. For example:
        I have aircraft x operating 40km directly north of the repeater on southwest rock on a search and rescue mission, the repeater's yagi antenna is pointed towards northwest ridge which is located west north west of southwest rock. The wave width of the yagi's beam is roughly 14 degrees which means the aircraft would be getting very low gain at the location north of the repeater.

        A dipole I think would be the only asset that can allow this multiple directional connection... However, how high a gain dipole can I get? Don't think size will be an issue

        Thanks for your help again, would love if we could have more regular/direct contact so that we can get more information going between us.
  • I can't see any LEDs. Mine are from Jdrones.

  • Hi,

    I just got my RFD900 modems from JDrones. They are cased in physically different casing than that of rfdesigns versions. And the air module comes with a telemetry cable whose connector does not snug fit the telemetry port on my APM2.5 board. I did not try to push it hard fearing something may get broken. However I was powering my board with usb cable and not by UBEC. Though I could read the ground module settings in config tool I could not connect the two modules in any way. I was wondering whether is it because of apm being powered by usb. Another problem with JDrones modems are, they have no status LED, which leads to confusion whether they are powered on or not. However I still finding ways to connect both modules with each other. Hope I get some heads up from you guys.


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