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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Could some one tell me how fast this little toy can operate and at what W.

My order for the DNT900 is coming in a week times. But they have restriction, running 500kb/s you are allow 85mW.


How's the RCLink going? We will be using this for long range telemetry and RCLink would be a great addition. Good results so far from the tests you've done. 

By the way, what is the best or recommended setup for this?

Look up the specs right from the source if you want to know details about the chip.  

Info page...




The specs Jake provided are for the raw si1000 radio chip.... but the RFD900 has a power amplifier and very high-gain amplifier on-board as well..... in summary it is:  1 Watt (+30dBm) transmit power, and air speed as high as 250kbps ( serial data rates as high as 115200), configuration dependent, of course.    typical usage for telemetry is with air rate at 64kbps, and data rate at 57600, for better range and lower error rates.

Details are here:  http://rfdesign.com.au/index.php/rfd900

Are the RFD900 ready for purchase? we will be using it here in the Philippines. The allowed frequency is 915-928 MHz. I'm not sure when, but my friend will soon be purchasing it since I already gave her the link,

RCLink is just a firmware update right? maybe i'll just update the firmware after the development is finished, though we could just use the Joystick control from mission planner for the meantime.

Looking forward to the RFD900. :)

Hello Delfin,

Yes, RFD900s are available on the web store: http://store.rfdesign.com.au

We have complete bundles with antennas, ftdi cables, regulators, to make integration easier.

RCLink, is in the "not-so-stealth-development-mode", It is a separate board which screws together with an RFD900, providing 12 channels of RC PWM IO and PPM IO ports.  As it gets closer to release will make some more announcements :)   -- It will be designed to fix with current RFD900 boards so you can have great telemetry now and soon, ultra long range RC control !

Ah. So will it operate on the frequency of the RFD900? Good news though. 

I haven't received confirmation of the purchase from my friend but she already started buying all of our needed stuffs.

For orders here in the Philippines, please lock the frequency to 915-928 MHz.


How to cook and freeze a modem.

The RFD900 modems are specified from -40 to +85 deg C.  This was tested, and performance across this range was verified prior to release.  But, we wondered how far can they *really* operate?

Setting the radios to transmit at full power (1 Watt), continuous spam of data, with duty cycle thermal limiting turned off we ran them through our environmental chamber.

Going cold, we got to -73 degC before we started to reach chamber lower limits, and the radios were happily sending data.  The radio was allowed to cold soak at -73 for 30 mins, then turned on and blasted at full power. -- No issues were seen!

Going hot, we had the radio transmitting at full power, while stepping up in 10 degree increments.

At 120 deg C things were all fine, on the way up to 130 deg C, the radio dropped link at 125 degC.  Ramping back down, the RFD900 locked on and recovered a full power link cooling through 123 deg C or so.  

Running through performance tests back at room temperature, no adverse effects were noted from the extreme temperature torture :)

I just got my DNT900 yesterday, It's pretty dam easy to set-up and get going.

Pretty impress it did 500-600 Meters.

The base station was inside a house on the bottom of the hill operating at 1watts.

Both the transmitter had the Quarter wave monopole.

I was walking uphill around the the suburb fill with trees and buildings.


It's going to be fun testing RFD900 out in the open.


I notice there are 6 GPIO, do I program the GPIO via the firmware?

I have a 1.5GHz Toy that I want to connect to this transceiver but it's logic is 3.3V. Is it possible to alter the serial of the RFD900 to work at 3.3. If not I would need ones of these right http://www.adafruit.com/products/395



Glad the setup was painless and you had them running OK !

The GPIO have not been assigned any functionality at the moment, but that is configurable via firmware.

I plan to get some AT commands happening to set/get these IO at some stage.

The IO levels are 3.3v nominal in/out, 5.0v tolerant, so, connecting it up to a 3.3v device will have no issues.

That GOOD I feel a lot safer now.

Hope this help some one, to Compiling SiK on Ubuntu 12.04

You must compile sdcc. Ubuntu 12.04 sdcc don't include sdas8051

Download link http://sourceforge.net/projects/sdcc/files/sdcc/3.2.0/

Dependency "apt-get install bison flex gputils"

Could you guys tell me if there is any way I could totally ruin my RFD900 with the firmware?

I'm guessing as long as I don't play around with the bootloader  I should be able to get into boot loader mode via connecting CTS and GROUND at boot up (http://code.google.com/p/ardupilot-mega/wiki/3DRadio#Forcing_bootlo...). Presuming from the bootloader I should have no issue restoring the firmware?


I used a binary precompiled package from sourceforge: http://sourceforge.net/projects/sdcc/files/sdcc-linux-x86/3.2.0/ on Centos - works OK.

It should not be possible to brick the RFD900 with user upgrades.  The bootloader is protected.

The 3DRradioconfigurator upgrader points to the most recent hex files on the RFDesign website, which are built from the latest trunk at RFDesign/Sik on Github.

On the RFD900, there are two pads (Pin 1 and 2) shown on the 9 way production header with "BOOT" written between them - they are the CTS/GND pads brought out for easy access.  It is visible in the physical pinout pic on the RFD900 product page.

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