My light bridge as arrived! Will it stand alone?

Discussion in 'Video Assist & Video Accessories' started by Chris Newman, Jun 4, 2014.

  1. Chris Newman

    Chris Newman Member

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    The specs on this thing are awesome. Pre-ordered in February, and it finally came. It's worthless to me if I can't use it as a stand alone. Anyone have experience with it or know of anyone else. I might to some test flights on my smaller rig at low altitude. :/
     
  2. Chris Newman

    Chris Newman Member

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    Researching the Specs.
    The lightbridge says it's on 2450Mhz and my Dx8 Spektrum says it's uses 2400Mhz.

    The lightbridge automatically switches from 30 channels to pickup the strongest one.

    The spektrum automatically switches from 79 channels to pickup the strongest one.

    Anyone have much knowledge off the 2.4ghz spectrum? Should I be ok to run them on the same heli?
     
  3. Tim Sessler

    Tim Sessler Active Member

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    Very curious to see how it performs. Also got one today but won't be able to test it until next week.

    On my Graupner MX20 I can see the quality and strength of the radio signal - is there anything comparable on the Spektrum?
    Before flying I'd walk away a few hundred feet away and see if there is any significant change in the quality or RC interference when the Lightbridge is turned on. Make sure to have a fail safe/coming-home set-up before you test a first flight.
    I really have no idea what will happen. They might coexist nicely - or it might mess up the Spektrum signal completely.

    Please let me know how your tests are going!

    Cheers. Tim
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Chris: The question cannot be answered by knowledge of the 2.4Ghz Spektrum itself -- it is only answerable if you know how the Lightbridge and the Spektrum use the 2.4Ghz Spektrum and what steps they take to avoid interfering with other traffic on that chunk of bandwidth.

    Andy.
     
  5. Chris Newman

    Chris Newman Member

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  6. Matt Sharp

    Matt Sharp Member

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  7. Sam Slape

    Sam Slape Member

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    I would suggest using the "range test" feature on your MX-20 while the light bridge is on and then again when it is off and see the difference between the two.
     
  8. Chris Newman

    Chris Newman Member

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    So I did some guniea pig work and flew the lightbridge next to my 2.4ghz spektrum! 4 flights and 30 minutes airtime with 0 control issues. Did a range test before hand with no effect on my spektrum signal.
     
    Tim Sessler likes this.
  9. Tim Sessler

    Tim Sessler Active Member

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    Awesome! Thanks for testing. Do you have any input on the latency? According to the DJI website it'd be up to 0.32 or even 0.4 sec when used with a 5D mk3 - which seems pretty useless: http://www.dji.com/product/dji-lightbridge/spec

    Will hopefully test it tomorrow with the Graupner MX20.
     
  10. Aj White

    Aj White Member

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    Well hot damn, this changes everything! I was completely disregarding that setup for that same reason... hmmmm.
     
  11. Sam Slape

    Sam Slape Member

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    It sort of makes sense when we know that wifi networks work within close range to each other... however I'm no expert on this!

    Does anyone know the operating frequency of the lightbridge channels?
     
  12. Chris Newman

    Chris Newman Member

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    I know the lightbridge says it's on 2450Mhz.
     
  13. James Cole

    James Cole Member

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    I did a test with light bridge where I had the tablet wifi turned on and lightbridge would only go 150-170 meters before loosing link. I turned off wifi on my tablet and got 1726Meters no signal loss. I think that in a long distance situation you will experience shorter range with competing 2.4 signals.

    forward to 3:00 for range


    8X playback speed, yaw twitch is just my shifty fingers
     
  14. Tim Sessler

    Tim Sessler Active Member

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    WARNING: DO NOT USE THE LIGHTBRIDGE WITH A GRAUPNER TRANSMITTER!!

    Finally got around to test the Lightbridge today - super excited and with high hopes.

    I used my Graupner MX-20 for the copter, Futaba 8FG for the MoVI and a Canon 5D mk3 going directly into the Lightbridge transmitter (that was mounted on the rear leg of the MoVI).

    The following thing happened during the range-check, which is probably the worst case scenario:
    Without the Lightbridge turned on, around 300 ft from the Graupner TX and Lightbridge Rx the RC signal of the copter was still perfect - the quality was all the way up at 100%.
    The moment the Lightbridge was turned on the Graupner RX quality went down to 5% and then lost the signal completely. So far so good - airborne this would activate the MK failsafe and initiate a come-home process. Unfortunately next up, the motors stopped and then restarted, while the Graupner RC signal was coming back in for a second and would then drop again. Which basically means that the Graupner Rx is actually picking up a Lightbridge signals, which will ultimately lead to some interesting and uncontrolled stick input (and crash?!).

    Long story short: please don't try this combo airborne!!

    As far as quality of the actual video feed: It seemed fine until about 300 feet out - though with the Lightbridge mounted next to the Futaba on a Secraft Tx-tray only a couple hundred feet would be possible before the first artifacts would appear.
    Also the latency with the 5D mk3 is above 300ms - probably closer to 0.5 seconds. Hardly usable for anything halfway serious.

    It would have been too good to be true - but with this test I have to come to the conclusion that this system won't be useful for any non-DJI copters and in no case will allow 100% perfect framing or allow for any accurate focus pulls or anything that would need a low latency.

    Cheers!
     
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  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    Let’s hear it for testing carefully! Glad you did that, Tim. You probably saved your copter, and some others’ copters, too!
     
  16. Gary Haynes

    Gary Haynes Administrator
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    Reminds me of testing I did with the GoPro3 Black. Put it on the dash on the car and drove down the freeway. Pass under a good marker like a bridge while watching it on the iPhone. One Mississippi, two Mississippi all the way to about 6 seconds. Decided that it probably wasn't going to work for FPV. "I know that I flew just up to the tree on my goggles and stopped. Honestly don't know why it slammed into it and exploded with cacophonous sound resulting in a plethora of loose parts."
     
  17. James Cole

    James Cole Member

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    I am wondering what your monitor is? Android device? If it is a tablet or phone do you have the wifi turned off? I have a LG G tab 8.3" tablet and when the wifi is on I get only 150-250 meters distance before complete signal loss. But with the wifi off and everyones phones on airplane mode, we get over 1700 Meters of perfect footage as seen above.
    Using MK I understand why you want to use the Graupner.
     
  18. Tim Sessler

    Tim Sessler Active Member

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    I was using a Small HD AC7. Wifi on the Android was off - though phones weren't set to airplane mode.

    You were using a DJI based copter for this test, right? Did you also use the Lightbridge for the RC? How well does it work?
     
  19. James Cole

    James Cole Member

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    Version 1.3 is out for Lightbridge this morning.
    What's new?

    *Improved Firmware upgrade speed.

    *Addressed the issue of failure to refresh version number when upgrade is finished.

    Click here for more information.
     
  20. James Cole

    James Cole Member

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    I used Lightbridge to control the copter. These tests are on a Phantom 2 with H3-3D gimbal, gopro Black 3+ and Futaba T8J. The connection link is great, I flew 1726Meters with no connection issues
     

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