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Antenna Tuner -- Replacing Roller Inductor With Switched

Discussion in 'Radio Circuits, Repair & Performance' started by KG7FIU, Jun 8, 2019.

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  1. KG7FIU

    KG7FIU Ham Member QRZ Page

    Have an MFJ-989C antenna roller inductor tuner. But hate the inductor component. Loose contacts, grinding, lots of arcs, plus it takes forever to switch bands / QSY even when it does work properly.

    Wonder if it would be possible to swap out the roller inductor component with an old-fashioned multi-position switch component that would still handle higher power. Something like the inductor the MFJ-962C has (see picture).

    Has anyone done this? Would it require additional circuitry, etc?

  2. AF7XT

    AF7XT Ham Member QRZ Page

    The above example if only for lead dress is flawed.
    Placing the switch contacts as close to the inductor as possible is key.
    One good example included. A Drake MN2700B

    270010.jpg 270011.jpg
  3. AI3V

    AI3V Ham Member QRZ Page

    It will work fine, and be a very easy, non-critical project.

    Try and use a coil about the same size, and a switch with as many positions as you can find.

  4. KG7FIU

    KG7FIU Ham Member QRZ Page

    ok, thank you for the feedback everyone!
  5. KD0CAC

    KD0CAC Ham Member QRZ Page

    Or you just solder to the coil that is in there .
    Just add a switch .
    G1OJS likes this.

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