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!

http://rfdesign.com.au/RFD900.php

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:

http://store.rfdesign.com.au/rfd-900p-modem/

Seppo Saario

rfdesign.com.au

 

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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.

Hi !

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 ?

Enes,

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.

-Don

@Don,

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.

Regards,

TCIII AVD

Enes,

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.

Regards,

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?

Hello,

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?

Sources:

http://www.rfdesignuk.com/LTEoverview.htm

http://www.rfdesignuk.com/LTEETSI.htm

http://www.rfdesignuk.com/Documents/LTE%20800MHz%204G%20FAQ%20v1.pdf

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.

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.

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