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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wow this is bad news. I guess the best solution is to just use 4g. 

3G/4G is not a good solution for flying devices. Wrong placement on vehicle can cause interference with electronics. Another big issue is with bandwidth etc, none of the telecom carriers are giving any promises of data rates and signal is often lost on rather low altitudes.

All telecom operators are expecting that all their mobile clients are on "ground" so antennas are naturally pointed downwards to maximize RF signaling. In cities where you have high-rise buildings you might get higher altitudes same goes on areas where you have some mountains closeby but on country side etc you can loose signal already on altitudes of 100-200m.

For multicopters 100m is usually ok but fixedwings often tend to fly higher altitudes especially if doing mapping missions.

So if you use mobile systems. Be careful and remember that you might loose all communications on low altitudes.

Hi Thomas, did you ever resolve this? I have the same problem between a 3DR compatible radio and an RFD900+

I'm not having any luck getting my RFD900+ talking to a 3DR clone (which talks very well with its other clone)

Is my problem format 25 vs 26, which I can't change? Do I need to flash different firmware?

Or do I need to disable ECC on both the RFD and the remote 3DR radio, even though ECC works fine on the 2 3DR radios together?

Thanks for suggestions.


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+

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