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Antenna for vhf+AIS

Discussion in 'Electronics' started by incoming, Aug 3, 2025 at 8:13 AM.

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  1. incoming, Aug 3, 2025 at 8:13 AM
    #1
    incoming

    incoming Active Member

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    I have an ic-m506 fixed mount on my 42 post sportfish that is connected to my garmin 8616xsv for displaying AIS targets.

    I would like to add a 2nd vhf and antenna and I’ll probably add a seperate class b or b+ AIS box now or in the future, depending on how everything prices out.

    For radios, I’m considering the garmin 115 or the ICOM m330 but open to suggestions. For the antenna, I have a 14’ galaxy 5230 on one side and a bracket on the other side to mount the second antenna. Would another 5230 be good or is there a better option considering I want it to eventually do double duty for AIS and VHF? I’ve heard mixed things about a VHF and class b AIS using the same antenna with a splitter but I’ve also heard some antennas are optimized for both sets of frequencies. I really don’t have a great spot for a 3rd antenna. I suppose I could mount a dedicated 4’ AIS antenna on my hard top but would that really be better than sharing one of the 14’?
  2. Capt Ralph, Aug 3, 2025 at 9:54 AM
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Use the big stick for long range, use a small stick for short range.
    You don't need to talk to mars when you need to call someone a couple of miles aweigh or less.
    You don't need to hear noise from mars when trying to listen to local reception.
    Put your AIS splitter on the small stick.

    If there is any loss from an AIS splitter, you don't want it on the big stick when you may really need that last fraction of TX wattage.

    The AIS and marine VHF frequencies are so close, Dipole length difference between to two is only an inch or two and AIS transmit power is just a few watts; I used an old VHF stick for years on my AIS.
    Mars does not need your AIS data anyway.
  3. incoming, Aug 3, 2025 at 12:43 PM
    #3
    incoming

    incoming Active Member

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    ha I guess not

    that said there are aesthetics to consider and anything other than a 14’ on the stbd side to match the port may look a bit strange
  4. Capt Ralph, Aug 3, 2025 at 2:07 PM
    #4
    Capt Ralph

    Capt Ralph Senior Member

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    Eh,
    Aesthetics vs Form/Function.
    Your call

    I'm an Icom/Simrad guy.
    Not a clue about Garmin.

    Pascal had some comments several weeks ago about Icom vs ??.
    If he doesn't chime in here, I'll try to find that thread.
  5. ranger58sb, Aug 3, 2025 at 3:04 PM
    #5
    ranger58sb

    ranger58sb Senior member

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    AIS frequencies are a smaller slice within the marine VHF frequency range.

    Shakespeare (probably among others) makes at least one antenna type where a version is optimized for marine VHF and another is optimized for AIS. Galaxy 5225s, I think, something like that...

    Not a recommendation, just an observation that might provide more data points for study...

    We selected our second VHF radio with the idea of loudhailer and auto foghorn in mind. Icom M510-something-or-other... but maybe they have others, too...

    -Chris
  6. Capt Ralph, Aug 3, 2025 at 6:02 PM
    #6
    Capt Ralph

    Capt Ralph Senior Member

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  7. Pascal, Aug 3, 2025 at 6:20 PM
    #7
    Pascal

    Pascal Senior Member

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    I ve always big a big fan of Icom when it comes to VHFs. I have a pair of 330 with built in GPS on my 53, good units, simple and easy to use. I like others I be had to deal with in the last like Ray.

    i ve recently added an Simrad / Navico AIS 500 with its matching Splitter. Easy install, works well.
  8. Capt Ralph, Aug 3, 2025 at 6:40 PM
    #8
    Capt Ralph

    Capt Ralph Senior Member

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    There you are. Was thinking now in Tennessee that you weren't talking to us any more.
    Beautiful high altitude & thin air. Even I would try to hide for a while.
  9. Pascal, Aug 3, 2025 at 7:01 PM
    #9
    Pascal

    Pascal Senior Member

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    lol… it s been cloudy today but I love sitting on my aft deck in August in 69 degree weather!!!

    forgot to mention I replaced an older POS Raymarine on the 110 with an Icom 510. Great vhf too although in all fairness I never use any of it s advanced features .
  10. Norseman, Aug 3, 2025 at 7:09 PM
    #10
    Norseman

    Norseman Senior Member

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    Do NOT get the Garmin 115..
    I had one for 2+ years and disliked it for a number of reasons:
    The display didn’t have enough backlight to be visible in bright daylight, especially with sunglasses on.
    Volume and squelch on the same knob.
    Small letters on the menu, hard to read.

    Ripped out the 115 a few weeks ago and sold it on eBay, installed a Standard Horizon GX 2410 instead, heads and shoulders above the Garmin, bright screen, big screen, squelch and volume on separate knobs and it has AIS with a built in splitter.
    Love it.

    https://www.thegpsstore.com/Standar...MI8NH0iuHvjgMVWq5aBR2tHDKeEAQYASABEgILHPD_BwE