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MFJ Tri Mag

Discussion in 'Amateur Radio Antennas' started by Mudfoot, Nov 3, 2018.

  1. Mudfoot

    Mudfoot Sr. Member

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    I got one today. I finally put a 2 meter in my old Cherokee. I dug out an old Comet SSB-22 5/8 NMO monobander, from the rafters.

    I read the Eham curmudgeon reviews, that pooped on it. To me, it's the ticket, besides I have extra NMO and UHF mounts I can swap out, if needed. I was going to remove the NMO and look, but didn't. My Comet is stiff and branches was knocking the little magnet mount I was using.

    Anyways, it's decently priced.

    https://www.dxengineering.com/parts...CZhQDTLmqJLOThPQ48axXY1vczkXdRyUaAiy2EALw_wcB


     
    Dmans, Tallman and Captain Kilowatt like this.

  2. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Good price for a triple mag.
     
  3. Mudfoot

    Mudfoot Sr. Member

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    I thought so, too. I got mine from Amazon. I paid $43.74 with free shipping. The powder coat looks good. I'm hoping it'll last a few years without rusting up.
     
    Tallman likes this.
  4. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    The stub on my magmount allows every hamstik I have to be used. The white pvc pipe carries eight antennas for 80 meters all the way up to two meters.

    [​IMG]
     
    Shadetree Mechanic likes this.
  5. Mudfoot

    Mudfoot Sr. Member

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    Nice...
    I like the PVC pipe idea. I usually drill hole, but getting tired of the hastle. This mag mount gives instant satisfaction and swaps to my other car quickly.
     
  6. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    I have had one for a while, used it with a screwdriver until I hard mounted it. They work fine.
     
  7. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    As long as you are not running crazy watts should be fine. I have even put one of my CB radio firestiks and talked driving the highway with it. It gets out there really well for a barefoot radio.(Uniden 980)

    Funny thing about the magmount, the connector does not care if it is CB or Ham radio.
     
  8. Shockwave

    Shockwave Sr. Member

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    Just wondering if the bottom of the magnets are all covered with the grounded conductive foil? If so, the value of coupling capacitance to ground is four times larger than most other magnet mounts. That's helpful for both low frequency HF use and higher power levels.
     
  9. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    My magnets do have any aluminum tape on the bottoms. I do clean the area well and might put down a little carnuba wax and clean the magnets before setting it down. I don't know what effect the tape would have since one side of it is covered with adhesive and there is no direct electrical connection.
    C=nka/d N= the number of plates, K= the dielectric constant, A=the area of the plates, divided by the distance between the plates. This is the simplified equation for capacitance..

    Where the magnets really shine is holding that antenna right where you put it.
     
    #9 Tallman, Nov 13, 2018 at 10:34 PM
    Last edited: Nov 13, 2018 at 10:58 PM
  10. Shockwave

    Shockwave Sr. Member

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    The magnet side of the foil that has the adhesive on it does get directly connected to the braid of the coax since its conductive side folds under the metal cover to make contact. Without the foil, the distance between capacitor plates is increased dramatically by the thickness of the magnet. Even the cheapest Radio Shack mag mount use to have foil on the bottom for this reason.
     

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