GPS interference caused by SPOT device

Discussion in 'Avionics and Upgrades' started by Arrow76R, May 15, 2019.

  1. Arrow76R

    Arrow76R Pre-Flight

    Joined:
    Jan 27, 2015
    Messages:
    80
    Location:
    Colorado Springs
    Display Name:

    Display name:
    Arrow76r
    Note the following Aviation International News article. I had this problem in my Arrow when I had my SPOT unit clipped to the passenger side sun visor. I finally noticed the GPS loss coincided with SPOT transmissions. I re-located the SPOT to the aft end of the right side middle window (away from the roof mounted GPS antennas) and all was good.

    **"FAA Cautions Aircraft Owners About GPS Issue Attributable To SPOT Portable Electronic Device**
    Aviation International News (5/14) reports that “aircraft operators have notified the FAA of several instances of an intermittent loss of GPS position information,” with the interference attributable to the utilization of a SPOT portable electronic device (PED). Due to “this interference, the FAA has published InFo For Operators 19006, which provides awareness to Part 91 aircraft owners, operators, and pilots on the safe use of SPOT PEDs,” and it “also reminds the flying public of existing regulations, policy, and guidance covering the safe use of PEDs on board aircraft.” The agency cautioned “that this GPS interference also affects aircraft systems that rely on GPS position data, such as ADS-B Out.” The FAA said, “The operator or pilot-in-command shall determine that using a SPOT PED does not interfere with the navigation and communications systems prior to operating under IFR.”
     
  2. benyflyguy

    benyflyguy Pattern Altitude

    Joined:
    Jan 1, 2018
    Messages:
    1,775
    Display Name:

    Display name:
    benyflyguy
    I have a spot that I use for my high altitude ballooning. I find that to only interferes but can easily be interfered with. I had it placed in my payload box with a 3M transmitter broadcasting packets every 60 seconds at 1.25 watts (on rubber duck antenna projectinf sideways out of payload) And the spot wouldn’t connect or transmit correctly. Using a Modifed J-pole antenna pointing down (creating a radio void above) cut down on most interference to the spot but was less then perfect.
     
  3. Arrow76R

    Arrow76R Pre-Flight

    Joined:
    Jan 27, 2015
    Messages:
    80
    Location:
    Colorado Springs
    Display Name:

    Display name:
    Arrow76r
    I wonder what the EIRP of the SPOT transmission is. Has to reach to GlobalStar satellites and GPS signals are SUPER weak!
     
  4. Jeff Oslick

    Jeff Oslick En-Route

    Joined:
    Mar 12, 2005
    Messages:
    3,843
    Location:
    Fullerton, CA
    Display Name:

    Display name:
    Jeff Oslick
    I've used a SPOT several times (placed on the glareshield, so about 4' from the GPS antenna) on long flights and not seen an issue. However, I have seen two handheld GPS units placed right next to each other interfere. How good your cable shielding is likely plays a role.