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:
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:
With fixed wing I think you would be O.K. for long range. Landing... not so much. The latency I have seen in the boat is barely noticeably if at even at all. Just my experience so far. I would not be comfortable using it with my Helicopter with a lot of camera gear on it however. Computer crashes and your screwed.
David R. Boulanger
Here's a revision to my enclosure design. This one is intended to mount to booms(tubes), masts, etc. Will custom make any clamp up to 30mm for you (ad shows 20mm boom):
I'm having a problem sometimes with the link quality being bad at boot up, even with both modems very close together (around 1 meter)
This also makes the "Getting Params" process slow. Is this process necessary or can I skip it?
I have now verified that if I use the RSSI debugging functionality with AT commands the data looks good, RSSI is around 250 and noise around 60. So it is something in the pixhawk logging.
I have a new problem. I bought a rfd900+ telemetry for a plane. My ground station has a rfd900 (old version). The first times everything was working very well. But now there are serious problems. I did several test... I took from a friend the non-original 3dr telemetry (915 mhz) and I use it on my computer.
My test results:
Plane: Rfd900+ Computer: Rfd900 (old version) Weak rssi
Plane: Rfd900+ Computer: 3dr Weak rssi
Plane: Rfd900(old) Computer:3dr Good rssi
All antennas works well (I test it) I understand my Rfd900+ telemetry has a problem. I install to rfd900+ a new firmware (1.9sik rfd900a) and I check all settings but the signal qualty problem not fix.
What do you think about this problem. Is it hardware problem or software problem ?
I don't know if it relates to your problem, but I found that my RFD900+ radios will not work with either my RFD900 or my 3DR radios unless I turn off ECC. With ECC disabled, they all work together just fine.
I was told the same thing by Event38 when I asked them why their version of the RFD900+ telemetry radios would not work with my 3DR telemetry radios.
How weak is your RSSI? I have noticed that at close range the signal is weaker but then as the distance increases it gets better. I don't know what power output your using but that has been my experience. I actually cannot connect to mission planner unless my vehicle is a good way away from me or if in my house its a few rooms away with the doors closed. I have also read about the ECC problem with using a 3DR radio and a RFD. Just what I've seen.
David R. Boulanger
The cover on top of my RFD900 keeps coming off so I was thinking about taking it off and potting the inside of the unit with some silicone or epoxy that won't cause damage and then placing the top back on. If I did this, would it cause the RFD900 to overheat?
I would say: Don't do that!
Most likely you either shortcircuit something on board or mess it's RF design and tuning. RFDs have specially designed RF PCBs and adding more material on it would most likely kill it's original design as epoxy/silicone will definitely alter resistances etc on board and components.
Why don't you just add small solder dots on the metal EMI shield. That would not cause any bigger harm..
RFD868 is no more a solution for Europe?
I live in Turkey so we have 900MHz GSM and 800MHz 4G LTE signals as general in Europe. I am trying to setup a long range UAV for academic purposes. I already have ezUHF which works on 433MHz band. So 433MHz 3DR is no option or I'll use 2.4GHz rc.
900MHz is no-go in Europe, so thanks to Seppo, they made RFD868+ so everybody in Europe bought them and use them happly. My researchs says new 4G LTE bands interfere with 868MHz devices a lot and reduce more than half the range.
So, RFD868 is no more a solution for Europe? Can anybody with RFD868 can confirm they get good range within 4G LTE coverage?
In PDF it says:
What types of 868MHz SRD are prone to 4G interference, is it only low cost receivers?
Unfortunately it’s not. Whilst a small number of SRD receivers have particular weakness at the 800MHz 4G frequencies, 4G user equipment is permitted to radiate high levels of noise directly into the SRD channel. There is very limited technical scope to design a receiver that offers immunity to this noise. Consequently, almost all receiver types across a broad range of complexity and cost, will suffer significant degradation in areas where 4G products are in operation.