First flight

Discussion in 'ALTA' started by Stefan Helborg, Jan 13, 2016.

  1. Stefan Helborg

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    Hi

    Well first actual flight with a camera mounted. The recordings are ok. I saw, however, that when I hovered the drone at the same place, the gimbal did a small pan by itself. It can be seen in the attached video recording. (don't know why Vimeo made the video look so blury)



    I balanced my gimbal, and then I hung my ALTA with gimbal in a string, and then I could set the stifness
    tilt 75 - roll 75 - pan 330

    I also notised that I lost my overview of volts (telemetry) at the Futaba remote control. Not on my screen, but on the remote. I have two Futaba receivers mounted on my ALTA ...

    Because that I have fitted a wifi booster on my MOVI controller, I could with the naked eye see, that I still had control of the gimbal at 475 meters.

    I already lost my HD signal at about 300 meters. I use a Connex to my downlink, and has mounted antennas as you can see on the attached photos. Any suggestions to extend this signal as 300 meters is too little.

    View attachment 9058 IMG_3558.JPG IMG_3560.JPG
     

    Attached Files:

  2. Michael McVay

    Michael McVay Active Member

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    Hi Stefan. I think you will need to check the installation of the Connex antennas. They are supposed to face 90 degrees apart from each other. From your photo it looks like you have both of the sides where the wire attaches to the antenna facing forward. My installation has one facing back and the other facing sideways (away from the movi). I think if you make those changes you will get much better range.
     
  3. Stefan Helborg

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    Thanks for the answer.

    Ok I thought that if both antennas pointed in the same direction (backward at me) that I would have a better signal.

    So you're suggesting, that I turn one of the antennas 90 degrees to the side so that it points to the side?
     
  4. Michael McVay

    Michael McVay Active Member

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  5. Stefan Helborg

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    Will try that :rolleyes:
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Stefan: imagine one of the antennae with its tip sticking into the hole of a doughnut (sorry about the Freudian image). The donut represents (in small scale) how the radio frequency signal propagates out from an antenna. You, on the ground, want to be in that doughnut. :)

    Andy.
     
  7. Stefan Helborg

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    Yes and in this case, I'm recieving two dougnuts instead of one, so I can't see why turning one of the antennas will give me a beter signal...

    I gues you where talking about the Connex antennas, and not the Futaba Telemetry problem right!
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yes. The Connex. I suspect there is a secondary reason for the 90 degrees apart is also that a whip antenna, such as they are, emits a linearly polarized signal, so by tipping one antenna over, it is emitting two different planes of polarization.

    Andy.
     
  9. Stefan Helborg

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    Today I flew again and had turned one of the Connex antenna 90 degrees as described in the installation manual. No difference. I lost the picture at about 300 meters distance.

    Already at 100 meters the image pixelated slightly when I made tilt movements.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I presume when you say "I made tilt movements" that it's the ALTA that's tilting not you and the transmitter, right? :)

    In my experience, when the copter tilts and interferes with the video downlink that's a sign that the transmitting antenna on the copter is either:
    1. Changing its polarization with respect to the receiving antenna and the tilt is reducing the amount of received signal as a result.
    2. Being occluded by some of the carbon fiber on the copter and needs to be repositioned.
    3. Just possibly, the transmitter is suffering from electrical noise being fed into it and one or both of the above makes matters worse.
    I would start with item 2. above and see whether you can make the signal come and go by, say, yawing the ALTA in a flat plane to test whether that might be the cause.

    Hope this helps.
    Andy
     
  11. Stefan Helborg

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    Yes, I will try that. I also talked to Connex, and will follow a couple of their advice. Among other set donwlink to performance rather than quality.
     

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