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Video Downlink Dropping Out

Discussion in 'Electronics' started by Andy Post, Jun 16, 2015.

  1. Andy Post

    Andy Post Member

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    Hey Thrill Seekers,
    I hope ya'll can help me find the weak link (pun intended) with my video downlink.

    What's hanging on my Movi M5...
    • Sony A7s is connected to...
    • Atomos Shogun is connected to....
    • Cheap Amazon HDMI to AV converter is connected to....
    • Immersion RC 5.8GHz 600mW TX
    That transmits to Turbo Ace monitors with build in diversity RX's

    My problem is that my solid transmission range, where I don't get drop outs is in feet and inches. If I'm more than 20' away, then the length of dropouts gets into the multiple seconds. I've had them last up to 10 seconds, so it's pretty useless.

    I've looked for interference issues by taking everything off the M5 and spreading it across the table to move components as far from one another as I can, even powering the Sony and Shogun with AC adapters and the HDMI/AV converter with a USB cable to eliminate battery and BEC interference. No joy.

    Where should I look for issues? I'm having a hard time believing that a simple antenna change is going to do the trick but will clearly grasp any straw that seems likely at this point.

    I'm even considering the Lightbridge but have concerns about interference with flight control.

    Share your thoughts.....
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    Have you tried different channels on the video TX and RX?
     
  3. Andy Post

    Andy Post Member

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    Will do just that. I also have a 2nd TX/RX to provide FPV and Telemetry from iOSD for the pilot. Same issue there, but not as mission critical if it drops for a sec or two as he never flies by wire. Thought it might be all the other electronics and carbon fiber, but eliminating them hasn't gained much. I'll try changing channels.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    What antenna are you using on the Immersion and the Turbo Ace monitors, Andy?

    The Other Andy.
     
  5. Andy Post

    Andy Post Member

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    I'm using what came with....

    Went to a friends RC shop this afternoon who had IBCrazy Bluebeam set he let me try in his shop. Seems that maybe an antenna upgrade might get me most of the way there....
     
  6. Jason Smoker

    Jason Smoker Active Member

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    Also a fpv monitors that does not blue screen or black screen helps. I tried using cheapo monitors even with the IBCrazy Bluebeam antennas you can only get so far!!1
     
  7. Andy Post

    Andy Post Member

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    I thought I was the other Andy???
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    No, no, I insist that I'm the other Andy...you're the other, other Andy! :)

    Yeah, upgrading the antennae is where I was headed too. The Bluebeams are pretty good. You really want to try and get good line-of-sight between the copter antenna and the ground antenna -- it keep the copter antenna clear of carbon fiber.

    The Other Andy.
     
  9. Andy Post

    Andy Post Member

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    Found a set of Airblades locally, also by Video Aerial systems, to try while I'm waiting for the blue beams to arrive. They seem to help a tad but it's hard to tell for sure. Raining cats n dogs here so I'm indoors with lots of metal about.

    I was also thinking about getting a short, flexible extension that would allow the antenna to hang loosely off the back leg of the M5 gimbal so that, once in the air, it would be below everything else, but would not have enough movement to every get caught on the gimbal itself or, heaven forbid, get washed up into the props.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The dangling antenna would be a good idea as a test, but I wouldn't want to fly with it like that as a permanent arrangement -- only because there's a risk that it'll get caught in something on the ground and cause a tip-over followed by a prop strike...

    The Other Andy.
     
  11. Andy Post

    Andy Post Member

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    I've got a little cable ordered, along with the Blue whoosits n I'll test it. Could be over reacting as the current feed is so horrible as to be useless. My gimbal operating skills are in the "developing" stage. Adding predictive tracking is beyond me at this point....
     

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