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Thread: MFJ 986 Differential-T Tuner ???

  1. #1
    "Island Bartender" KG4CGC's Avatar
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    MFJ 986 Differential-T Tuner ???

    Anyone ever use one?
    What are your opinions?
    Pros, cons Etc.

    http://www.universal-radio.com/catal...tune/0706.html

    Buddy has a used one so I'm not paying anywhere near that price but just asking of the Islander's experience.
    Looking at a Johnson Matchbox too but it lacks WARC band tuning.

  2. #2
    Whacker Knot WØTKX's Avatar
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    Well, the Matchbox might tune WARC, with a particular antenna.

    I have a used MFJ-989C on the way, the old Dentron is getting goofy mechanically.

    MFJ is OK, you may have to open it and do minor repairs. It's really a 1K+ tuner, as is mine.
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    Diff t's are just a roller and one cap. I Think. Might be limited tuning. Try it. See what happens. As you know MFJ power rating is like a quarter of what they say. I Like this heath 2040A. You can tune a screen door. I mean anything, And tough as nails. 3000 watts. Giver Er
    Last edited by N9FE; 06-06-2010 at 05:47 PM.

  4. #4
    Conch Master KJ3N's Avatar
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    Quote Originally Posted by N9FE View Post
    Diff t's are just a roller and one cap. I Think.
    Not quite. Two counter rotating caps on a single shaft. This means that you will only find one tuning solution; the correct one. On most tuners with 2 cap controls and 1 inductor control, you can find multiple tuning solutions. Not every solution you find will be the most efficient one. Differential-T tuners will find the most efficient solution and it will be the only one.

    Might be limited tuning. Try it. See what happens.
    See above. The "limited tuning" is a misunderstanding of a Diff-T tuner. If the Diff-T won't load it, there's something wrong with the antenna system. This was pointed out to me when I had to add a bit of ladder line to my doublet to get it to tune 15m. It was fine everywhere else, but 15m. After adding about 7 feet, no more issue.

    As you know MFJ power rating is like a quarter of what they say.
    Actually, about half. ;)
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  5. #5
    "Island Bartender" KG4CGC's Avatar
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    Thanks so far.
    On the Match Box, it has the Viking logo and comes with the directional coupler. Not sure what direction it's going in.

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    My matchbox would never tune ten. I played with the feed line lenght about five times. It helped. But ten would never quite go. Now with the 2060a no prob. 60 meters warc bands, ten.. Its all good

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    I have the manual on PDF for the matchbox with the directional deal if you want it.

  8. #8
    "Island Bartender" KG4CGC's Avatar
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    Quote Originally Posted by N9FE View Post
    I have the manual on PDF for the matchbox with the directional deal if you want it.
    Sounds cool. I have no clue about Johnson Matchboxes but I'll try anything once.

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    "Island Vampire" KB3LAZ's Avatar
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    Quote Originally Posted by KG4CGC View Post
    Anyone ever use one?
    What are your opinions?
    Pros, cons Etc.

    http://www.universal-radio.com/catal...tune/0706.html

    Buddy has a used one so I'm not paying anywhere near that price but just asking of the Islander's experience.
    Looking at a Johnson Matchbox too but it lacks WARC band tuning.
    I have one, it works. Though Im not fond of it..I got it after my 989 crapped out. In retrospect I I should have got a Palstar. I use the 986 for 40/80/20 with my amp but it seems to have a limited tuning range. Soooo I tweaked my antenna a bit and now dont use a tuner...well I use it on 20 still.

    "A night sky full of cries. Hearts filled with lies. The contract: is it worth the price?"

  10. #10
    "Island Vampire" KB3LAZ's Avatar
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    There was a matchbox at the hamfest today. Look to be in good order. It was 60$ I believe.

    "A night sky full of cries. Hearts filled with lies. The contract: is it worth the price?"

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