Welcome to InspirePilots.com

Join the leading DJI Inspire community for free!

RC to Copter interference sources

Discussion in 'Inspire 1 Discussion' started by RaptorMan, Jan 12, 2016.

  1. RaptorMan

    Joined:
    Dec 18, 2015
    Messages:
    770
    Likes Received:
    214
    I searched but didn't see what I was looking for so...

    Since part of the comm link is at 2.4GHz and much of the wifi signals are in this band it's been said that flying in an area with a lot of wifi will cause a lot of interference with the I1 and I guess that makes sense. There is also some question about what to do with closer sources of RF -- things like cellphones and the blutooth and wifi hotspot functions they can have. Is there any consensus on this?

    So, if my tablet has cellular service should the cellular service be shut off during flight? If the tablet does not have cellular service but is connected to a wifi hotspot from a phone is that going to be worse than the cellular signals?

    I can see that any signal in the same band as the comm signals between RC and copter would negatively effect the comm so does everyone set all there devices to airplane mode to turn off all RF emissions?


    Brian
     
  2. Packetdancer

    Joined:
    Dec 25, 2015
    Messages:
    32
    Likes Received:
    10
    Interference aside, I would put the phone into airplane mode anyway once you've cached the GPS maps; getting a text or a phone call while you're flying could be pretty bad.
     
  3. RaptorMan

    Joined:
    Dec 18, 2015
    Messages:
    770
    Likes Received:
    214
    I'm thinking the worst interference situation would be smartphone with cellular connection talking to tablet over wifi, but such an arrangement wouldn't have a text or phone call problem I wouldn't think -- just a noisy RF environment with cellular and wifi signals competing with the RC-copter comm.

    It would be worse if you were using the cellphone as your FPV display as that could receive a text or call.

    Another situation which might be the least or nearly the least would be a tablet with cellular connection but not able to receive phone calls or texts. Obviously having all the devices in airplane mode and RF silent would pose the least RF interference threat but you'd not have a connection to the internet at that time.

    I guess I'm just trying to see how big of an issue this really is as it would be quicker to not have to cache the map data and be able to fly with a cellular tablet so maps can be pulled as needed.


    Brian
     
  4. crashburn

    Joined:
    Jan 3, 2015
    Messages:
    310
    Likes Received:
    160
    A couple of months ago I was filming flooding in our state in the back woods, well away from civilization and any wifi interference. At the first 3 locations I could not get very far without loss of signal which was very troubling. Finally we determined that my driver, in a 4 wheel drive truck with a tall CB antenna on top, had inadvertantly left his CB amplifier on, which was under the driver's seat, even though all CB radios were off. So, interference can come from other sources than wifi…
    But, I've used my cell phone hotspot many times with my tablet, for live maps, without obvious interference.
     
    #4 crashburn, Jan 13, 2016
    Last edited: Jan 13, 2016
  5. Jay Baldwin

    Joined:
    Apr 30, 2015
    Messages:
    66
    Likes Received:
    23
    Location:
    Branford, CT USA
    Using my "other" rig (X8+) for a survey, I lost comms flying close to an older cell antenna on a building that had not been disabled. I was flying using the 900mhz band and the bird went down like a rock. Still haven't been able to confirm everything, but the AC inverted while on a programmed mission and landed in a salt water pond. Needless to say, toast. I've always been extremely careful with pre-flight checks, etc, but got stung on that flight.
    No issues with my DJI Inspires or Phantom 3P, but still, don't tempt disaster and be aware of your surroundings and potential interference. I even put my key remote as far away as possible to avoid glitches
     
  6. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,723
    Likes Received:
    3,880
    This again has been debated until the cows come home. Many swear leaving all their phones etc turned on has caused no issues whatsoever.

    However, there is always the possibility that the front end of a receiver can be swamped with close proximity RF even if it is not on the same band/frequency. A simple harmonic from a badly designed final output stage can cause a receivers AGC to throttle down and subsequently lose the signal it is meant to be listening to.
    My attitude is why take the chance? I put everything into airplane mode prior to a flight and it is written into my ops manual checklists as a pre-flight check.

    My personal thinking is it may well not cause problems in 999 cases out of 1,000 but I don't want to be that thousandth flight - so I take that potential problem out of the equation.
     
  7. RaptorMan

    Joined:
    Dec 18, 2015
    Messages:
    770
    Likes Received:
    214
    Again, very helpful info. A topic like this has lots of room for speculation and I can see pro's and con's of staying connected to the internet but on balance it makes sense to have everything off or in airplane more prior to power up of the RC and Inspire.

    My first flight last week I used my old tablet which doesn't have cellular but I had it connected to my phone hotspot and neglected to turn that off. There was no problem and I had good signal out one half mile when I couldn't keep my eyes on it so I turned around and came back.

    I'm hoping the Windsurfer style parabolic reflectors reduce interference and it's that fact more than range extension that made me pick one up. Of course, getting 50%-100% greater range give-or-take doesn't hurt either even if you never push that far.


    Brian