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Adding a non-marine antenna tuner to the boat

Discussion in 'SSB and Ham Operators' started by Brian D, Jun 23, 2017. Add this thread to a FAQ

  1. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    3,367 posts, 263 likes
    Lancer 27PS
    US Oceanside, Ca MCB Camp Pendleton, Ca KF6BL
    I am still in the process of finishing my SSB installation. Just lost motivation recently but it seems to be coming back.

    With the demise of the Kenwood TS-50, I purchased an Icom IC-707. It is an older radio but like the TS-50, it has very little in the way of bells and whistles. Simplistic sums up this radio. It has been opened to allow all band Tx. Not that I will ever use it, but...

    As part of the on-going project, I will be installing a 35' Alternate Backstay Antenna. It will be connected to an MFJ-939 automatic antenna tuner. The MFJ is not marine grade by any stretch of the imagination. So one must improvise, adapt, and overcome.

    I purchased a watertight box off of eBay to use as the housing for the tuner. The tuner is attached with #4 sheet metal screws to the bottom of the box. The screws are driven into the rubber feet. This seems to hold well but it might come loose under harsh sea conditions.

    The three entry points are for control (left), radio (center), and antenna (right). Ground is on the right side of the box. The glands are sized for .25" cables. The antenna cable will be GTO-15.

    I have a sea dog cable gland coming for the GTO-15 to exit the deck.

    So there we go. Got that portion of the project done. Maybe it was enough to get my motivation back up. We will see.

    DSCF4479_1.jpg
    DSCF4478_1.jpg
     


    Rick D likes this.
  2. Rick D

    Rick D

    Joined Jun 14, 2008
    6,235 posts, 85 likes
    Hunter Legend 40.5
    US Long Beach, Shoreline Marina, CA
    That should do!
     


  3. windward54

    windward54

    Joined Mar 12, 2008
    544 posts, 5 likes
    Jeanneau 49 DS
    US San Pedro, CA
    Looks good. Time to get this up and on the air.
     


  4. Rick D

    Rick D

    Joined Jun 14, 2008
    6,235 posts, 85 likes
    Hunter Legend 40.5
    US Long Beach, Shoreline Marina, CA
    Brian, can you point me to that waterproof box? I couldn't find it on e-bay although I did find some that will work? I like yours better.
     


  5. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    3,367 posts, 263 likes
    Lancer 27PS
    US Oceanside, Ca MCB Camp Pendleton, Ca KF6BL


    Rick D likes this.
  6. Rick D

    Rick D

    Joined Jun 14, 2008
    6,235 posts, 85 likes
    Hunter Legend 40.5
    US Long Beach, Shoreline Marina, CA
    OK, got a different box for the IT-100 tuner which is smaller. I decided to sell both the ICOM M700 and the AT-120 tuner as a set (on e-bay). We'll see... Thanks for the idea.
     


  7. Rick D

    Rick D

    Joined Jun 14, 2008
    6,235 posts, 85 likes
    Hunter Legend 40.5
    US Long Beach, Shoreline Marina, CA
    Hey, all: I am mimicking what Brian did. So, the antenna connector is for coax; the antenna is GTO-15. At least I think; insulated wire. So, how do I connect that to a coax lead?
     


  8. vhoisington

    vhoisington

    Joined Mar 13, 2011
    114 posts, 20 likes
    Islander Freeport 41
    US Longmont, CO (SF Bay) Longmont
    Sounds like you know what you are doing.

    I already have the radio (Icom 802) and the auto-tuner installed. For some reason the antennae is missing. My boat an Islander 41 Freeport Ketch, has a separate tang mounted on the Mizzen for a "backstay" antennae, I have the lead out of the auto-tuner up through the deck and I assume there is a point to mount this at teh top of the Main mast. My two questions.
    1. What do you use for an insulator at the top and lower end of the antennae wire?
    2. What type of wire are you using for your antennae

    I already have a trip up the main mast planned and would love to be able to get this working at the same time.
    Great to read/see your progress. Keep the story going.

    Thanks,

    Victor
    S/V Desiderada
     


  9. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    3,367 posts, 263 likes
    Lancer 27PS
    US Oceanside, Ca MCB Camp Pendleton, Ca KF6BL
    @Rick D , the GTO-15 looks and feels exactly like RG8X. So you can solder a PL-259 to the GTO-15 and connect it to the antenna tuner. There is no shield on the GTO-15 so no worries there. The ground lug from the tuner will connect to a screw you install on the box like I did. It will be connected to whatever you use; KISS, seawater, engine block...

    @vhoisington , I use wire-rope. The same material used for lifelines. Any insulator will work. You can make your own with PVC pipe or order "egg insulators" from ebay or Amazon. The lead from the tuner you see will connect to the bottom of the wire you run to the top of your mast. The top most insulator should be about 2' (5cm) from the top of the mast. Length of wire can be any but recommend >23' (7m).
     


  10. py26129

    py26129

    Joined Oct 25, 2011
    390 posts, 6 likes
    Island Packet IP31
    CA Lake St. Louis, Montreal
    Perhaps a dumb question, but does the tuner produce any heat?

    Matt
     


  11. Rick D

    Rick D

    Joined Jun 14, 2008
    6,235 posts, 85 likes
    Hunter Legend 40.5
    US Long Beach, Shoreline Marina, CA
    Exactly what I needed to know. Thanks Brian!
     


  12. vhoisington

    vhoisington

    Joined Mar 13, 2011
    114 posts, 20 likes
    Islander Freeport 41
    US Longmont, CO (SF Bay) Longmont
    Thanks Brian, that info helps a lot

    V
     


  13. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    3,367 posts, 263 likes
    Lancer 27PS
    US Oceanside, Ca MCB Camp Pendleton, Ca KF6BL
    @py26129, yes it does, but only when the turner is NOT tuned correctly to the frequency being used for the length of antenna. It is important, IMHO, that the length of the wire being used as the antenna can be matched, or tuned. If the length is correct and the tuner is happy, no heat per se.

    This is a very good read: Using Auto Tuners
     



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