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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          • There's a reason he is asking this. Sometimes it's just not possible! This is especially true in a search and rescue as you have to be prepared to search where needed not just where you happen to have a repeater set up. Also if you are looking for something as small as a person you need to fly low aka out of line of site. 

            • ground based repeaters are not possible in this application because people being searched for pick the location and not the searchers.  i plan on having the high flyer as close as possible to the low flyer while still maintaining line of sight with the command center.  there will be loss of signal in this situation and for that we will count on the autopilot to continue the mission during those drops in coverage.  i don't expect the ranges to be over three or four miles from the high flyer to the command center.   we will use the high power rfd900+ units on at least the link from the high flyer to the command center and probably on the low flyer as well.  

              has anyone ever done this?  i know we did in support of the cruise missile back in the 70-80's during testing but the high flyer was huge,manned, and had an active tracking antenna.  if i get the TM to work well then i will try the same thing with the video from the low flyer.

              Thermal imaging is obviously the final step of the development for this system.  Using a thermal imager would allow for much easier location of people in terrain at night.  First we would use a normal thermal imager like the tau2 but would eventually like to see development of a 360 degree thermal imager similiar to the 360cam we intend to initially use on the low flyer during daylight searching. ( http://360.tv/ ).  we are awaiting our 360cam to be delivered - video will be recorded for post flight analysis but also viewed in realtime using links back to the command center and wi-fi in the field by searchers in the area being grid searched by the low flyer.  lots of system and processes to develop and test here - we are busy.




  • I just got a 3DR V2 radio set form ebay and it won’t link to my RFD900. They work with my older 3DR radios and my RFD 900 works with V1 but not V2. I have checked the settings and reloaded the firmware. Any ideas?




    • I got it working. There is a link up issue if the airspeed is below 48. I was running 32 for more range. Worked all last year but not with my new radio.

      Does anyone have a technical explanation why this is happening?




      • Has anybody tried the MP SiK V 2.5 firmware?  I have V2.4 running now  but am curious to try the latest version.  I don't have the tools to build it.  Can anybody here upload an .ihx file?

        I would really appreciate it.


    • Developer

      If that ebay link you provided is accurate, then, no you did not buy a "3DR V2 Radio", what you bought is a clone, made by an unknown company, using unknown electronics quality, unknown assembly quality, unknown firmware revision/s, unknown factory quality control, unknown calibration values.     Oh, and the seller describes the "brand" as 'HK", so it might be hobby-king, or it might just be made by someone in HongKong, who knows.  

      • The 3DR radio its' self is just a carrier board for a cheap Chinese radio module.  Dissing "clones" in this case is pretty silly.

        • Developer

          Jake, I didn't "diss" anything.   I just pointed out the facts.    The facts are also that the 3DR radio contains a "module" manufactured ( and factory quality controlled) by HopeRF ( HM-TRP) , and advertised that way, and which is then assembled with a power system, antenna, case, etc,  and *tested* and quality controlled by 3DR in their factory before making it to customers.  It's not really a matter of where it's made, it's a matter of whether it's actually what it says it is "on the box", and you can know that with confidence. 

          Also, RFD900 radios are most definitely not just made from other people/s "modules".   I've personally been to the place they are manufactured, and it's not "cheap chinese" at all.      :-)

    • Plug the RFD900 into your laptop running Mission planner via USB and open the initial configuration -> optional hardware -> 3DR radio and click to load configuration. Take a screenshot. Then do the same with the 3DR radio. Make sure everything in the configuration matches.

      I have the 3DR radio v2 working with the RFD900 no problem.

  • Would this antenna be an improvement for a 915 3DR radio?


    Antenna for 915Mhz, 3dbi Dipole
    3dbi Telemetry antenna for your UAV needs, great little antenna for jD-SiK Radios
This reply was deleted.


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