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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Yes, you have to turn off ECC on both.


Thanks Don. Sure enough it works with ECC turned off. 

So the next questions are

1) How bad is it to lose ECC for mavlink/ardupilot?

2) Is there a firmware I can put on either radio so that they are compatible with ECC turned on? Or should I forget about it/not bother?



Multi-point setup

This is my first post on this thread so forgive me if the question has already been answered. I have three RFD900+ modems for airplane, GS, and Antenna tracker. I have Pixhawk on all three. I just programmed the RFD900 modems with B2.6 firmware and setup for node 0 aircraft, node 1 GS, node 2 antenna tracker.

Now for the questions. It all works on the ground and I plan on doing a flight test in the morning but the rssi and remrssi in MP don’t look like they are working correctly. They read between 6 and 8 when they are usually around 200.

Do I have something configured incorrectly?

Do I really have a very week signal?

Or does the current airplane firmware not support RFD900 with V2.x firmware?




Hi, the radio link reporting is not working on the multipoint fw. I contacted RFDesign and they are working on it.

Thanks for the reply. Did they say how long before the next firmware update?


I did some flying this morning and everything worked perfect. The Pixhawk based antenna tracker works very well.




No they didn't say how long it would take, but I am looking forward to it. None of my rfd868p modems work on the standard fw so I have to run them with MP fw. The link is solid but no RSSI reporting..

Noob in RTK question;can i use 868+ modems for both telemetry and connection to RTK GPS...or i have to use 433 for telemetry and 868+ for rtk?

Emin, I think you may use the same 433 or 868, just set them to different band, but if you feel rich use 1 433 and 1 868+

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!

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