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Help with downlink data connection lost

Discussion in 'Pro/Adv Discussion' started by MikeyOnline, Apr 26, 2016.

  1. MikeyOnline

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    Started using the Healthy Drones site today. Was wondering if I could get a read on my log from today as I see a couple of things that concern me. One is that I get a half dozen or so "Downlink data connection lost" and always for between 1.3 and 1.7 seconds. I'm flying with my Nexus 6 phone in airplane mode and I've never seen a video dropout even out to about 1700 feet from home, and the signals on the camera display are always maxed. Never had any trouble with control and it has never done a RTH. But... I'm wondering if those could cause a RTH at some point? The P3P is completely stock and on today's flight (below) I maintained line of sight the whole time. Antennas were angled up about 45 degrees as usual so that when I hold the controller, the antennas are almost perpendicular to the ground.

    Also, I'm wondering about cell #1 in my battery base on the minor variances detected.

    HealthyDrones.com - Innovative flight data analysis that matters

    P.S. I did find a couple other threads here but those seem to be combined with loss of FPV or longer times on the data connection loss.

    Thanks,
    Mike
     
  2. RocketBrew

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    Location:
    Arizona
    Best signal will be when the antennas are perpendicular to the aircraft, not the ground.
    [​IMG]
    Due to the "Fresnel effect", even line of sight does not mean a full signal between the TX and RX.
    [​IMG]
     
  3. MikeyOnline

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    Thanks for the helpful diagrams. I do realize that perpendicular to the craft is optimal but I find it difficult to maintain that due to the phone being in the holder on top: I don't want the antennas touching or very close to the mobile device and it's a bit difficult to get perfect tilt while still being able to view the device. And as you fly the craft farther from the home point, the farther you go, the closer perpendicular to the ground and perpendicular to the craft become. The thing that is confusing to me is that it appears to be maintaining full signal strength, I never get any FPV dropouts, and the data link dropouts are almost all 1.5 seconds. It's as if something in the Phantom is "cycling", causing interference or maybe there's an intermittent connection inside the craft (or RC) somewhere. I don't even know if those reports are "real" because today's flight stayed very close to home and before that I flew 1700 feet from home point, again with no loss of FPV (not even a signal glitch) and the P3P always responded to all my inputs... yet I see these intermittent 1.5 second data link drops on every flight.

    Mike
     
  4. alokbhargava

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    You are losing the link even before taking off. What was wrong at the site?
     
  5. mavrik33

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    Seems like alot of nexus users have had issues. I was having little drops in signal like u until I positioned my antennas the way the drone directions told me to
    So if you can figure out a way to to get ur antennas not so close to ur phone it will help. I've noticed keeping the remote pointed toward the drone helps to. Sometimes you have to adjust and watch the signal strength
     
  6. MikeyOnline

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    Never had any issues with flight or video. Only way I would know there was a problem was Healthy Drones. I'll try a better phone position but the holder and RC leave a lot to be desired. They really need another pivot point on the holder so you can get the phone away from the antennas. And I wish you could rotate the antennas 180 degrees to angle them DOWN instead of up! That would make the most sense because angling them up forces you to hold the RC at an awkward angle.

    Mike
     
  7. MikeyOnline

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    Still scratching my head on this one. Here are the notifications from today's flight. Keep in mind that the FPV video is smooth and steady and I would definitely notice this many 1.5 second drops if the video feed really froze that long, that many times. I'm wondering if it's a false error because if these didn't come up in the Healthy Drones notifications, I'd never know anything was "wrong" in the flight. Flight was perfect:

    A 00m 00s 0.0 ft 0 ft Mode Mode changed to GPS_Atti
    B 00m 02s -1.3 ft 0 ft Data Loss Downlink data connection lost for 1.6 seconds
    C 00m 02s -1.3 ft 0 ft Mode Mode changed to AutoTakeoff
    D 00m 02s -1.3 ft 0 ft Tip Taking off
    E 00m 02s -1.3 ft 0 ft Tip Return-to-Home Altitude:164FT
    F 00m 04s 3.0 ft 1 ft Mode Mode changed to GPS_Atti
    G 01m 16s 150.6 ft 0 ft Data Loss Downlink data connection lost for 1.6 seconds
    H 02m 26s 159.8 ft 612 ft Data Loss Downlink data connection lost for 1.5 seconds
    I 03m 03s 160.1 ft 672 ft Data Loss Downlink data connection lost for 1.6 seconds
    J 03m 28s 159.4 ft 671 ft Data Loss Downlink data connection lost for 1.6 seconds
    K 03m 40s 159.1 ft 672 ft Data Loss Downlink data connection lost for 1.5 seconds
    L 04m 18s 159.4 ft 414 ft Data Loss Downlink data connection lost for 1.6 seconds
    M 05m 03s 160.4 ft 93 ft Data Loss Downlink data connection lost for 1.3 seconds
    N 05m 53s 159.8 ft 93 ft Data Loss Downlink data connection lost for 1.4 seconds
    O 07m 03s 159.8 ft 93 ft Data Loss Downlink data connection lost for 1.5 seconds
    P 09m 11s 135.2 ft 38 ft Data Loss Downlink data connection lost for 1.2 seconds

    Mike