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Successful 900 Mhz 3DR Telemetry Maiden Flight

Posted by Trent at MyGeekShow on August 4, 2012 at 2:53pm

 

We finally made it!

We successfully completed our maiden flight with the 3DR 900 Mhz telemetry module on board our Shrike, it was incredible to see it gathering, transmitting, receiving and displaying live information... we can't wait to use it on future flights.

Thank you DIYDrones and community! This is so much fun...

-Trent

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Comments

  • Rick Eis August 11, 2012 at 3:59pm

    So what would be a good video frequency system to with this 900 Mhz telemetry unit?

    Is it possible to use a 900 Mhz video system or would we be sure to have problems?

  • Rana August 5, 2012 at 11:29am

    Andrew, based on my query in RCGroups forum also, they have updated the product web page, now every thing is clear.

    • Air Data transfer rates: 4, 8, 16, 19, 24, 32, 48, 64, 96, 128, 192 and 250 kbit/sec ( User selectable, 64k default )
    • UART data transfer rates: 2400, 4800, 9600, 19200, 38400, 57600, 115200 baud  ( User selectable, 57600 default )

    For two antenna ports, they said;

    Two antenna ports are used for diversity. The Si1000 has built in diversity support such that it will select the best antenna for every packet. Both antennas get used for transmit and receive, depending on which has the best signal.
    If you have a specific requirement for one antenna to transmit, the other to receive, it is possible to modify the open source firmware to do this.

  • Rana August 5, 2012 at 3:41am

    What highest baud the RFD900 would support with APM, without any link loss ?

  • Rana August 5, 2012 at 3:37am

    Andrew, what is the maximum RF baud of the RFD900 ?, It is nowhere mentioned at the product page.

    Why two antenna port ? Are both ports transmitting - receiving ? Or one port is only dedicated TX port and the other dedicated RX port.

    Generically receivers only have been seen with diversity antenna. 

  • Lloyd Breckenridge August 5, 2012 at 1:09am

    Try the reset button on the osd after the camera and transmitter are powered up.

  • Developer
    Andrew Tridgell August 4, 2012 at 9:41pm

    Hi Trent,

    I'm glad the telemetry is working well for you!

    For your cross-country flights I'd really recommend you get one or two of these:

    http://rfdesign.com.au/index.php/rfd900

    Those radios use the same firmware as the 3DR radio you have now (so they are compatible, and can talk to each other), but they have 10x the transmit power, and a high gain low noise receive amplifier. You can expect a range of over 70km with omni antennas. The RFD900 is right on the legal limit of what you can transmit in the 900MHz band in the US (ie. 1W, 30dBm), whereas the 3DR radio is 100mW.

    The only other thing I'd recommend you watch out for is interference with your GPS. You may keep GPS lock, but the signal could be degraded. If using the 3DR radios for a long distance flight I'd recommend you get a 900MHz low pass filter like this one. If you get the RFD900 you won't need that, as they have a low pass filter builtin.

    Cheers, Tridge

  • Developer
    Jason Short August 4, 2012 at 9:19pm

    I feel underdressed at the flying field now...

    Be sure to change the default ID to a random number or risk loosing telemetry when flying with friends.

    Jason

  • Dave August 4, 2012 at 9:19pm
    Good stuff guys.

    Mark your blog is a great resource and I'll be checking it out.
  • Sam Kelly August 4, 2012 at 8:48pm

    Trent, you could try updating the firmware on the OSD (I'm assuming you're using the MinimOSD). We were still shipping units with MAVlink 0.9 firmware, while APM and the Planner were now on MAVlink 1.0. Updating should be pretty easy with the OSD config tool.

  • Carl La France August 4, 2012 at 6:45pm

    Excellent  I have been following your progress Have a great day! 

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