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Losing GPS Signal

Discussion in 'Electronics' started by DOCKMASTER, Nov 25, 2025 at 8:13 PM.

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  1. DOCKMASTER, Nov 25, 2025 at 8:13 PM
    #1
    DOCKMASTER

    DOCKMASTER Senior Member

    Joined:
    Feb 26, 2012
    Messages:
    1,614
    Location:
    Ketchikan, Alaska
    My boat was just delivered via transport ship to Mexico. All systems were powered down and batteries disconnected for the 11 days it was aboard the ship. Just about everything came back to life well. Except my SIMRAD electronics suite keeps losing GPS signal. It finds a signal and connects to satellites just fine. But after 15-20 mins it loses GPS. I rebooted the system 3 times with same issue. My GPS antenna is inside a dome and well protected. Obviously I will check connections and such but it’s weird that this just started happening today. There is no sign of impact damage to the dome that houses the antenna and nobody was aboard while it was being transported. Any other suggestions on what to look for? I need to make my final 115 mile run Thursday to the new home and would really like to have a fully functioning plotter as I’m in unfamiliar waters. Yes, I have my iPad with Aquamap app and all charts loaded for this area for back-up if needed. But sure would prefer to have my SIMRAD monitors showing me where I am.
  2. Capt Ralph, Nov 25, 2025 at 9:14 PM
    #2
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    14,088
    Location:
    Satsuma, FL
    There are tables and lots of built in thingies that we will never understand.

    Turn it on and leave it on for a day or two.
    If the latest tables do not down load, you may need a software update.
    These updates usually come thru the Simrad MFD when it is connected to the web. All needs to be powered on for a while for this also.
  3. mapism, Nov 26, 2025 at 4:48 AM
    #3
    mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    2,273
    Location:
    Sardinia
    Are you sure it's "just" an antenna?
    I mean, old plotters used to rely on a passive antenna, typically connected with a coaxial cable, but the GPS "intelligence" was inside the plotter itself.
    But nowadays, most of what we are used to call GPS antennas are actually self-contained GPS units, that directly transmit the converted signal to the plotter via NMEA cables.
    If as I would guess you've got the latter, in the worst case you can simply buy another one and swap it. No need to find an identical one, any of them should work.
    And they are reasonably cheap, these days...
    Last edited: Nov 26, 2025 at 4:58 AM