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P3P: Do I lose direct control if "downlink" goes to zero?

Discussion in 'Pro/Adv Discussion' started by wsalopek, Oct 2, 2016.

  1. wsalopek

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    Hey folks...couldn't find the answer...

    I had assumed that if the "downlink" signal strength went to zero...(and video stops updating...and Litchi says "signal lost"), that I would also lose direct control of the Phantom, and that the Phantom would initiate RTL.

    But is that true?

    Or is it the UPLINK that needs to go to zero before control is lost and RTL is automatically initiated?

    Thanks...

    --

    Bill
     
  2. alokbhargava

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    In general, downlink contains video stream and telemetry whereas uplink contains commands to AC. Having said this, even if the video goes bad, you can control your AC if uplink is working fine.

    I'm not sure how Litchi determines signal lost state. If you are using Litchi, signal loss will not initiate RTH as AC will continue on its mission which is loaded to it when it starts flying.

    When signal is lost for over 3 seconds, your AC may trigger RTH, hover or landing based on settings. If you are using Litchi, it will continue on its path.

    I don't know how signal lost is decided, it's definitely not on zero signal strength. It's based on "limited" acknowledgement of command signals. LightBridge doesn't follow standard wifi protocols.


    Sent from my iPhone using PhantomPilots
     
    ROD PAINTER likes this.
  3. msinger

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    Your Phantom will not RTH until the remote controller signal is lost.
     
  4. wsalopek

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    Thanks for that.

    Just to be clear for others reading the thread...signal loss, at some point, WILL initiate RTH if flying in a mode OTHER than in "waypoint" mode.

    Otherwise, thanks for the clarification.

    So it sounds like the UPLINK needs to go to zero before control is lost...however, like you said, we're not sure at what point of signal loss/degradation, the Phantom will decide when to initiate RTH (and this would be independent of a person using DJI Go or Litchi, or some other app, correct?).

    --

    Bill
     
  5. wsalopek

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    msinger...

    Thanks for that...and of course you are referring to the "uplink" signal strength, correct?

    --

    Bill
     
  6. msinger

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    There are two signals -- the remote controller signal and the video downlink signal. I'm referring to the remote controller signal. The video downlink signal is not needed in order to fly.
     
  7. wsalopek

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    Thanks msinger.

    --

    Bill
     
  8. m0j0

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    For me the easiest thing to do is look at your TX. Guys correct me if I'm wrong. If I lose video signal I look at the TX. If the light is green that means you still have control with the TX. However, if you have control, don't have video and can't see it. You need to get it back anyway. Hit the RTH and wait to regain the video then cancel RTH.
     
  9. wsalopek

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    m0j0,

    You bring up a good point.

    From looking at the manual (page 28), it looks like:

    1) Solid green means control AND "HD downlink" (video/telemetry?) are good.

    2) Red and green/red and yellow (alternating...why so many colors?) means the "HD downlink" (video/telemetry?) has been lost, but you still have control.

    3) Solid red means control has also been lost.

    --

    Bill
     
  10. m0j0

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    Interesting, I have yet to see anything but Red or Green. So the in between is a bunch of flashing lights on the TX LOL. Good to know.