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RFD900, RFD900+ - New long range radio modem

Posted by Seppo on May 25, 2012 at 8:15am

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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Replies

  • Marc Dornan May 11, 2018 at 4:12pm

    Dragonlink v3 does all of that with full bi directional Mavlink. 12 channels. If you get the 1.5W RX you can also have 40km of range. Not DIY though. Google ULRS if you want DIY.

    Roger Ronald said:

    Michael,

    Thanks for the scope shot. I'll note that it appears to show 9 channels and I have heard other people indicated that's the limit for FRSky.

    But, I don't think it's definitive for the RFD900x radio yet....if you only put 8 (or 9) channels in, you'll only get 8 (or 9) out. It's possible that the radios may accept more channels and output them on the other side of the link.

    Most RC transmitters seem to only send 8 or 9 channels of PPM. They can send more channels with other protocols (e.g., CSRF, SBus). Some receivers scan definitely output 12 ch PPM (e.g. TBS Crossfire), but their ground comm protocol when their radio is plugged into an FRSky side is CSRF....since the limit would be 8 (or 9) channels. Even if I have to mux in the other PPM channels on the ground after exiting the TX, I can deal with that.

    Question for Fred F is, what DIY UHF radio are you using? Some of them sound good, but they don't fully support MAVLink up and down. I want to be able to send ground station commands and parameters up...and reliably get all the telemetry down.TBS Crossfire supports this....but I keep getting telemetry dropouts every five to 10 minutes or so...which breaks the MavLink connection.

    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…
  • Roger Ronald May 11, 2018 at 3:23pm

    Michael,

    Thanks for the scope shot. I'll note that it appears to show 9 channels and I have heard other people indicated that's the limit for FRSky.

    But, I don't think it's definitive for the RFD900x radio yet....if you only put 8 (or 9) channels in, you'll only get 8 (or 9) out. It's possible that the radios may accept more channels and output them on the other side of the link.

    Most RC transmitters seem to only send 8 or 9 channels of PPM. They can send more channels with other protocols (e.g., CSRF, SBus). Some receivers scan definitely output 12 ch PPM (e.g. TBS Crossfire), but their ground comm protocol when their radio is plugged into an FRSky side is CSRF....since the limit would be 8 (or 9) channels. Even if I have to mux in the other PPM channels on the ground after exiting the TX, I can deal with that.

    Question for Fred F is, what DIY UHF radio are you using? Some of them sound good, but they don't fully support MAVLink up and down. I want to be able to send ground station commands and parameters up...and reliably get all the telemetry down.TBS Crossfire supports this....but I keep getting telemetry dropouts every five to 10 minutes or so...which breaks the MavLink connection.

  • 3qs7z40lxxok2 May 11, 2018 at 2:52pm
    well that's bit sad if its only 8 my diy uhf module has 16 with mavlink
  • Michael Nunan May 11, 2018 at 6:31am
    I have been using the PPM over RFD900x for a while.

    I think that there are 8 channels passed through the RFD900x - I have not tried to put more through.

    Here is a view of the signal coming out of the UAV end of the link.

    https://photos.app.goo.gl/4njbjv7YHnPtZJgc2
  • Roger Ronald May 7, 2018 at 5:05pm

    I've googled for hours, but I still can't find an answer.....

    How many PPM channels are support by the RFD900x?  8 or 12 (or something else?)

  • Roger Ronald May 7, 2018 at 2:48pm

    There is a parameter to keep the plane from speaking for a delay period. Set the TELEM_DELAY parm to the number of seconds you desire. You’ll see “no input data” for that length of time, but it then starts up. I had problems with MinimOSD failing until I delayed the start. I got about 90% about 90% success at 7 seconds…so now I have the daly set to 15 seconds for my plane. There’s some sort of sequencing problem that this must fix.

    Thomas Stanley-Jones said:

    Isn't it always after you ask the question that the answer presents itself. We've figured out that the radio can't handle a constant stream of data when it boots up. If we wait to plug in the data wire until moments after booting up, everything is fine. It's the radio in the relay that's transmitting to the basestation that's giving us problems. The UAV is constantly chattering so it's as if it can't handle the noise when it wakes up in the morning. How would you set up this circuit so this problem isn't encountered? I can only think to have a switch that you turn on after the battery is plugged in.
    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…
  • John May 7, 2018 at 11:27am

    HI Guys, 

    Maybe my question has answer within the 60 pages, but I was not able to read them all. I hope you will be able to help me.

    I would like to know if we need to fly 60km using the RFD900x, will it be possible? it is a fixed wings plane

    We will use diversity antennas on the UAV and Yagi 14 dbi on the ground. The altitude of the plane will be 300m.

    The Ground station will be at 3 meters height. 

    We will put the radio in the wing. 

    Also we saw those antennas from VAS: which one is better for our solution?

    VAS 900 MHz BAZOOKA DIPOLE : https://www.readymaderc.com/products/details/vas-900-mhz-bazooka-di...


    and VAS 900 MHz TELEMETRY DIPOLE https://www.readymaderc.com/products/details/vas-900-mhz-telemetry-...

    and VAS 900 MHz BAZOOKA DIPOLE https://www.readymaderc.com/products/details/vas-900-mhz-bazooka-di...

    and VAS - 900 MHz Vee Antenna https://www.readymaderc.com/products/details/vas-900-mhz-vee-antenna

     

      

    Cannot Find Product...Searching
    The best quality First Person View equipment. Free or discounted shipping on all orders.Drone Racing, RC Airplanes, FPV Cameras, FPV Goggles, Video T…
  • Thomas Stanley-Jones April 10, 2018 at 6:05pm
    Isn't it always after you ask the question that the answer presents itself. We've figured out that the radio can't handle a constant stream of data when it boots up. If we wait to plug in the data wire until moments after booting up, everything is fine. It's the radio in the relay that's transmitting to the basestation that's giving us problems. The UAV is constantly chattering so it's as if it can't handle the noise when it wakes up in the morning. How would you set up this circuit so this problem isn't encountered? I can only think to have a switch that you turn on after the battery is plugged in.
  • Thomas Stanley-Jones April 10, 2018 at 5:52pm
    Alright, I'm back. I've decided to use two RFD radio sets. Radio 1 is on the UAV and communicates with Radio 2. Radio 2 is in the Relay box mounted on a mast some distance from the Pilot. It is connected to Radio 3 using the Tx/Rx wires (Tx to Rx and vice versa). Radio 3 then communicates with the basestation. I'm having a really hard time getting the connection to be stable. Sometimes the basestation connects to the UAV at the same speed and ability as if there was no relay (once out of 20), but usually it connects in super slow mode where it is barely operating. Sometimes when I cycle the power on the relay, one of the radios starts in boot mode (solid red LED). It's so random and uncontrollable. Anybody have experience like this?

    I've seen this with RFD900x using it to send data from an instrument to a computer. Each time it boots we have to cycle the power of the radio 1 to 5 times before we get a solid connection.
  • Dan Ho January 15, 2018 at 7:56pm

    If you were really going to go the home-made USB cable route, CAT-5e would be a good choice.  Here's some rated to -40C. Not sure about price but probably fairly cheap: 

     generalcable.com/assets/documents/LATAM%20Documents/Mexico%20Site/Cat%C3%A1logos/Cable-Solutios-for-the-Industrial-Automation-Market.pdf?ext=.pdf

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