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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  • Glen,

    Please first ensure you have version 2.4 or later. There was a bug with ppm record on earlier versions.
    If yours isn't let me know, and I can send you the correct version.
    PPM input or outputs pins can be configured for your ground and air radios respectively.
    Set up PPM input and output before recording fail safe ppm signal.
    The air side radio should also record your desired PPM signal in the even of radio link loss. 
    ( You can do this with remote AT if you like, note it will give an error if you try and record the ground side).
    You should set your controls to whatever will let you flight controller know that something is wrong,
    Then type in the AT command to record the ppm stream. Check in Mission planner that the signal is correct, then record it.
    Put your controls back to normal and check mission planner has returned to normal, then turn off your transmitter and ground and check that mission planner is going into the correct mode for a fault.
    AT commands are:
    1. for PPM input (ground)(pin 15 of header GPIO1.1,GPI1_1R/CIN ) "ATI16 = 1 "
    2. for PPM output (pin 15 of header GPIO1.1,GPI1_1R/COUT ) "ATI17 = 1 "
    3. to record the PPM stream for link loss "AT&R"
    The PPM input will need to be level shifted down to 3.3V as it is not 6V tolerant, which is likely the level coming out of your transmitter.
    You can make one up with 3V zener and 1K resistor, or we will hopefully be selling adapters for this soon if you are not familiar with this yourself.
    Note you can't configure both PPM input and output on one device as they are the same pin and you will have to disable one before enabling the other.
    Note also that you configure the correct end and don't mix them up.
    Once configured you should be able to control your aircraft using the radio and use mavlink at the same time.
    Note, you might notice it's not quite as responsive due to delays, but it is very flyable. 
    If you're drone racing, it might not be what you're after. (maybe in the next version of firmware this might get improved on).
  • good news, something is happening so. Nothing in http://rfdesign.com.au/products/ yet.

  • Hi Guys,

    Just got my new 900x in the mail last week. I am hoping to connect a D4R-ii for rc control. Seppo assures me this is possible on the model which is why I get him to send me the new improved model. Not exactly sure how this is done yet or which pin my signal wire should connect to. So if anyone else has had success doing this.....? If not, then standby for further updates.

    My current standard 2.4ghz system sends RSSI signal strength back to Taranis for audible feedback for FPV so I am hoping this will also be possible.

    Any comments in this area will be great.

  • what is the difference with 900x?

  • Any update on RFD900x release date ? or test results ?

    Seppo said 1-2 months in May...

  • Seppo, 

    I have a couple questions before ordering. Could please provide me an email? ( I just added you as a friend )



  • Just a random update ! - We have FREE DHL Shipping worldwide for this weekend, ending on Monday for all orders over $100 AUD. Just use the coupon code WOW to enable this :) Wishing all a nice weekend from all here. Seppo

  • I am working on an application for search and rescue where i need to relay telemetry from a low flying (search) vehicle to a high flying (relay) aircraft that re-transmits it to a ground station that is not in line of sight with the low flyer (search) vehicle.  has anyone used these modems for that purpose?  i had planned on using 3dr type transmitters but would rather get the range these seem to offer.


    • RFD has a relay system for their modem so as to use one as repeater

  • Hi All, 

    I got a couple of these RDF900+ radios and they communicate okay to each-other from my copter to mission planner, However, the range is the same as the  3DR radios.

    Do I need to change some configuration to accomplish longer range? 

    Can they be used with 3DR? and if they do, what configuration should I use?

    Picture attached.

    Thank you to all in advance for your help.


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