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



Views: 112726

Reply to This

Replies to This Discussion

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.



Hi Chris,

Thank you for your advice. I use the 3DRRadio config for configuration. But I did not found the option to inject the MAVLink RSSI. Could you tell me which configuration tool you use? 


Hi Jason,

No probs, we are all here to help each other.  Try the RFDesign site.  http://files.rfdesign.com.au/tools/ should have the RFD config tool which has the option 'Mavlink' in the lower left side.  This should inject mavlink RSSI messages in if it detects MAVLink is being used, it seems to strip the other RSSI messages out so it doesn't confuse the GCS.

Also I was running an SSH session over the link at the same time and it worked well.


It has been a long time since updates!

We have been working on a lot in the background.

A 900 MHz RCLink solution will be available very soon, within the next 1-2 months.

Telemetry plus concurrent PPM passthrough.
Modems with higher data rates and encryption (finally) are in the works.

We have prototyped the units and pretty happy with their performance.

Sorry for not revealing too many details just yet, but, letting everyone that we are very much on the case.

If there are some people keen to beta trial units and give them a good workout, please send a PM..

Also wishing to thank you for your support over the years.


Hi Seppo

Help me to understand a little more how these things work. 

When you say

1. "Telemetry plus concurrent PPM passthrough." what does that exactly mean? Same modem ca be used for different functions?

2. "Modems with higher data rates and encryption (finally) are in the works." What is the advantage of these features? 

My additional question is that, I figure that some GSM networks use the same band 900MHz, or even other broadcast could be using this band or near it. Now remembering from when i was a child, we grew up near the border with Malawi, some of National radio Channel when listening to the radio, you would also hear in low voice in the background another channel talking. I remember back then radios had a fine tuning knob, so to get rid of the background interference we had to fine tune with the fine tuning knob. In the AUV operations how does interference with other broadcast that may be using same band or nearly same band play part? is there even interference at all? Enlighten me a little on this one please!


Reply to Discussion


© 2020   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service