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Loading coil adjustment

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KK4VGT, Feb 26, 2021.

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  1. KK4VGT

    KK4VGT Ham Member QRZ Page

    I have a window mount MFJ-1600T. Do I need to adjust the tap on the coil or will a tuner do that. Also what tuner wood you recommend. I have a 100 auto tuner and a icom 7200. Any help will be helpful. 73's Bill KK4VGT.
     
  2. WD5GWY

    WD5GWY Premium Subscriber QRZ Page

    Having a tap on a coil means it has to be adjusted manually.
    If you have access to an antenna analyzer, you can use it to see the effects of different tap locations to bring down the SWR for the band you wish to operate on.
    A tuner will help give you some tuning range ( to a point ) without having to readjust the tap.
    If you don't have access to an antenna analyzer, you can set your radio's transmit power to 5 watts or so and use the built in SWR meter to adjust the tap.

    James
    WD5GWY
     
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    MFJ-1600T makes no sense in this context.
     
  4. RW4HFN

    RW4HFN Ham Member QRZ Page

  5. KH6AQ

    KH6AQ Ham Member QRZ Page

  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The MFJ-1600T is a mast extender, not an antenna.

    Do you mean MFJ-1622?

    If so, you must tap the coil per the instructions. On the highest frequency band like 6m, you probably tap it to bypass the coil completely, leaving the coil effectively out of the circuit; but on the lower bands it absolutely needs the coil in circuit and using a "tuner" at the radio end of the coax won't make it work.
     
  7. KK4VGT

    KK4VGT Ham Member QRZ Page

    Yes it is a 1622 I did put a 1600t on top end of coil. Works very good. Can you replace the coil with one you can adjust from inside and not have to go outside to change bands. Thank you for your reply. 73's KK4VGT Bill.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    You're describing a "screwdriver" antenna, which has the provision for continuously changing its loading coil remotely, via a control line.

    Those are surely available, but they're obviously much heavier than the MFJ-1622 and also considerably more expensive.

    Check models from Tarheel, Scorpion, et al. These antennas use a motor drive to change the coil and are usually powered by 12Vdc, reversing "tuning direction" by reversing the polarity of the applied voltage.
     
  9. KK4VGT

    KK4VGT Ham Member QRZ Page

    Yes that is what I need. The price of a tarheel is not a problem. I just don't to do it manually. Thanks 73's KK4VGT.
     

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