Automatic antenna tuners

Discussion in 'General Technical Questions and Answers' started by AB6KX, Dec 13, 2020.

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  1. AB6KX

    AB6KX Ham Member QRZ Page

    Hi All.

    I am looking for an auto tuner. I am only going to be running 100W station and want a tuner that can handle digital modes. I have heard that some blow up when dealing with 100% duty cycle modes.

    the ones i have been looking at so far are: MFJ-929, MFJ-993b and LDG AT-200Pro II.

    Im open to others that may exist too. Id ideally like one that can handle the full 100 watts. Am also trying to keep it under $300

    thank for the feedback

    back on the air after 25 years
  2. N5TJD

    N5TJD XML Subscriber QRZ Page

    I can't speak for any except the MFJ 993B. I never ran 100w in to it on a 100% duty cycle digital mode, but I used it a lot at 50w FT8 in to a ladder line fed 135' doublet on just about every band (except 160m), and I never had any problems. Good luck.
    AB6KX likes this.
  3. KU3X

    KU3X Ham Member QRZ Page

    I have an MFJ 929 and never had an issue with it. It has a much broader tuning range than the LDG models. It also has much better features.
    Two features I think are important are:
    1. You can set the SWR tuning point. In other words, you can tell it to not stop looking for a resolution until it finds a 1 to 1 SWR. If it can't find that
    low of an SWR it will stop at its lowest tuning point.
    2. If your antenna already has a low SWR the ATU will go into bypass automatically.

    Barry, KU3X
    KN6LDH and AB6KX like this.
  4. W4HWD

    W4HWD Premium Subscriber QRZ Page

    I had an LDG-200Pro II and it was a good one. Nice matching range and programmed easy. Only reason I let it go was I upgraded to the Elecraft KPA/KAT500 "PowerCombo".
    AB6KX likes this.
  5. W4NNF

    W4NNF XML Subscriber QRZ Page

    I've used an LDG auto-tuner, an IT 100, for years on digital (FT8/4, PSK31, RTTY), and it has never had a problem. OTOH, I've never operated with more than about 75 - 80 watts on any of these modes (or 50 with RTTY), so YMMV ;)
  6. AE1N

    AE1N Ham Member QRZ Page

    I have nothing but flowers for the MFJ-993B which I got on sale from HRO. I used to use manual tuners and had to create lists of antenna tuner settings. This tuner was a wonderful surprise but after 2 years, it is my bread an butter. I run two phased 43 foot verticals. Once the tuner memorizes all the different bands settings, and I load up on all 11 bands, 6 meters through 160 meters, it dutifly "snaps" in the proper LC values everytime I QSY. I like the safety features: when it says 300 watts, when you run over about 320 watts, it automatically kicks itself out of the circuit. Also most of the time I run about 100 watts output so I can use the 150 watt settings which are more diverse.

    Download the owners manual from MFJ and study it; there is a little bit of a learning curve.
    You will be very happy using one.

    ---Layne AE1N
    W9FL and AB6KX like this.
  7. AI6DR

    AI6DR XML Subscriber QRZ Page

    I've been using my MFJ tuner for many years with out any problems. I hate to say this but I first had a LDG but every once in awhile it would retune while transmitting during a qso
    AB6KX likes this.
  8. W9FL

    W9FL Ham Member QRZ Page

    MFJ 993B. Bullet proof. Tunes anything.

    I am running FT8 200Watts from a Kenwood TS 480 HX no problem.

    I have a couple LDG tuners, but they want you to run only 33 percent of their rating with high duty cycle modes, and they don't have as wide a matching range.

    One of my LDG tuners is an AT-1000 proII, but you can't run anywhere near rated watts with a high duty cycle. It gets extremely hot and would fail. Max is 330 watts high duty cycle. Running 600 watts caused the glue that fastens down the toroids, to start to melt.
    KU3X and AB6KX like this.
  9. W9FL

    W9FL Ham Member QRZ Page

    It's a shame the LDG tuners can't compare to MFJ.

    LDG makes some nice quality products. But the MFJ tuners have surpassed them
    KU3X, KN6LDH and AB6KX like this.

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