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Professional Antennas stowed = lost connections?

Discussion in 'Phantom 3 Help' started by DDW, Aug 24, 2015.

  1. DDW


    Aug 16, 2015
    Likes Received:
    I've had my P3P for about a month, 50 flights, no issues including after the most recent FW update. Until yesterday. One flight in the morning went out to about 600m, no issues. Then in the afternoon, I took it out about 800m at 50m' altitude, had LOS, 12 satellites, good FPV feed. I started getting some intermittent video dropouts and a video feed warning at the edge of that range. Having read the posts here, I did not panic, just turned it around and started bringing it back home. Then about 30m away, I got (I think) a very brief compass error message, followed very quickly thereafter by an "atti mode" warning. Within a couple of seconds the P3P had started drifting away from me in the wind (I tried to manually control it but I realized later that I was not giving it enough stick input, totally my fault) and I immediately pushed the RTH button on the RC and I immediately got a message that RTH had been initiated. It was at that point that I said "oh sh*t, the antennas are stowed!!! (@#%$&^@), I put them up, after a short time the bird went back into GPS mode, and continued RTH until I cancelled RTH from the RC button and landed. This whole sequence from the first ATTI mode warning took place in the span of about 45 seconds.

    So obviously I screwed up by not having the antennas properly out and aligned. I understand that this would have an effect on the video feed. But I can't imagine why this would cause a compass error message or why it would put me into ATTI mode. Would this be expected behavior? Just trying to make sure that I understand how this process works. Obviously the RC was still connected because my RTH instruction went out immediately and was followed perfectly. Plus I don't believe that there was a red light on the RC (ps I did not see the "toilet bowl" on my flight log playback).

    I have calibrated the compass since the recent FW update but have never done an IMU calibration because I have not had any issues. I have never had any warnings or error messages about the compass until yesterday. I check my compass MOD values before each flight and they are consistently in the 1500-1600 range.

    Lessons learned: follow checklist; align antennas properly, learn how to fly in ATTI mode, RTH is great but know exactly when and how it works.

    On related issue, what is the difference between forced ATTI mode and switch to ATTI mode? I understand that when in ATTI mode but with the switch in GPS mode, the bird will re-establish GPS mode when/if it is able to do so, and that with the switch in ATTI position it will not change into any other mode by itself. Is there any reason why I should have immediately flipped the switch to ATTI mode rather than just keeping the switch where it was?
    Any thoughts? Thanks for all of the great insight on this forum!
  2. bbfpv

    Feb 3, 2015
    Likes Received:
    Long Island, NY
    It was a coincidence. And everything else you said is correct. Since it seemed to be a controlled situation it was fine leaving it in P-ATTI and waiting for it to pop back to GPS. In situations where the bird is out of control, flipping to ATTI manually will usually recover control and you can bring it back home.