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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Hm...thanks for answer but i really doubt that....that would mean i can use DragonLink V3(http://dragonlinkrc.com/store/dragon-link-advanced-complete-system) for PPM control and also connection to pixhawk and ground station telemetry and also for communication with RTK...hope that day will come soon...

Hi Seppo,

I am using two RFD 900+ for radio control. 

I have question about how to get the RSSI value. As I know I can get the RSSI value by entering the AT command mode. but that will interrupt the communication. So currently I enable the RSSI debugging and parse the debugging text from radio module to get the RSSI value. 

However, there are two problems. one is the RSSI debugging text is reported too often, about 6 messages every second, that result in too much data. The other one is that RSSI debugging text can be mixed in the application message sometimes, that will cause corrupted application message. 

Do you have any suggestion on how get RSSI value while application communication is on going? 

Thank you very much!

Are you using MAVLink?  If so why not have it inject the MAVLink messages with the RSSI?

thank for your reply. Chris.

No, the MAVLink is not used. Do you mean that if MAVLink is used, RSSI value can be in MAVLink message?

I am a little confused. I'd like to get the RSSI from RS232 interface and show it on a display. 

Could you please explain a bit more? Thank you!

Hi Jason,

Yes if the data stream going across is MAVLink and you have inject MAVLink RSSI turned on (it's a config option) then yes it will automatically inject MavLink RSSI tags into the data stream.  I was very happy to see this on a test setup last year.  The test was a pixhawk connected to a companion PC running MavProxy which was connected to an RFD900+ to another RFD900+ which was connected to a PC running Mission Planner.  All RSSI readings were coming from the RFD900's which was great.

I plan to have a look at the firmware on how it's doing this but yet to get to it.  If you need the data but dont want to use MAVLINK packets maybe have a look at how the firmware does it and write your own custom version.


Hi Seppo

Whaat does this statement mean "Long range >40km depending on antennas and GCS setup.". What GCS setting and antenna would ensure this range?

Thanks in advance


It might imply a tracking antenna mount controlled by the GCS and a Yagi antenna.



Thanks Thomas for quick reply.

So, would Yagi antenna be better than that the Omni? If so would you recommend which make and model of the yagi? I am preparing to assemble an X-Talon so presently I'm putting together a list of what is needed.

Thanks once again.


Antenna theory and matching components properly is something you may want to look into.  A Yagi is directional and the Omni is not.  It also depends on the airspeed, duty cycle, and a variety of other factors you program into the radio.


David R. Boulanger

Hi David

Your advise is really appreciated, thanks; as you have been aware that this no field of my expertise. In this case I think I will for now stick with Omni using the RFD900 modems.

Many thanks.

I'm no expert.  Read as much as you can and there is a lot to learned on YouTube video's about antenna's and matching equipment properly.  The antenna's that come with the RFD seem to be of good quality.


David R. Boulanger 

Thanks mate!


I'm doing a lot of research and so when i read something that is unclear I tend to ask just like I did here. Thanks all. Yes, the current Talon I have uses RFD, at some point I had some problems with the link quality even when the plane was close to the GCS. Updating the firmware/drivers solved the problem. I'm yet to range test the plane, I have not flown it any further than 5km. So, I’m ken to see how these antennas perform.



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