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AT auto with 6400

Hey gang

I've been reading the conversations about the AT and HF auto tuners by Palstar. I would love to control the tuner directly from the flex without using 3rd party software, so if I understand it right, the AT will follow the flex as you tune just by using the usb on back of radio?

Now are there any pros and cons between the AT and the HF auto, as far as how they work, and things. I know the AT has the needle meter and the HF has the digital readout. any other differences I should know about?

Thanks for the opinions and help



  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator

    The HF Auto is rated for higher power handling capability and is currently sold and supported by PalStar. The HF Auto has 3 antenna outputs (3 SO-239 connections).

    I believe Kessler Engineering is still doing repairs on the AT Auto but I would email Don Kessler to confirm that. The AT Auto gives you an SO-239 out as well as balanced line out. Don Kessler has the patent on the AT Auto.

    I've owned both and the AT Auto can be directly interfaced to the 6400 via USB to serial cable. This allows the tuner to track the radio's TX slice frequency. Direct connection does not allow controlling the tuner (operate/standby) or selecting between the coax or balanced outputs. If you connect the AT Auto to a PC then K5FR's DDUtil program allows more control of the AT Auto, but requires a PC at remote site.


    Dave wo2x

  • WX7Y
    WX7Y Member ✭✭✭

    I have both the AT-Auto and the HF- Auto and can tell you from years running the AT-Auto and a couple years running the HF-Auto, the AT-Auto is a dream to run as it has two things going for it OVER the HF-Auto, 1st with a FTDI RS-232 plugged directly into the FLEX radio the AT-Auto follows the FLEX great, The 2nd thing that shines on the AT-Auto is the ability to run your HF AMP's PTT through the tuner so the AMP will not key-up when the Tuner is tuning.

    The AT-Auto at my station run's full legal power and has done for years.

    The HF-Auto is my backup Tuner on my backup station and sits most of the time on the shelf un-used for the lack of DIRECT RS-232 control and the PTT bypass.

    One thing to remember the HF-Auto has a low power limit of 200 Watts when off or in by-pass mode because of the Relays used.

    The AT-Auto may also have this issue but it has never affected me or I haven't heard of it BUT to be fare it uses the same relays as the HF-Auto.

    The HF-Auto has a little better tuning range at least on my Antenna system's then the AT-Auto.

    When I get the Tuner-Genius in a month or so and it works out then the HF-Auto will be up for sale as the Tuner-Genius has these features built in as well and will become the main station tuner and the AT-Auto will become the backup.

    As Dave said, Kessler Engineering can repair the AT-Auto if you need it repaired but not sure what the parts availability there still is because it has been out of production for a long time now.

  • Harold Rosee
    Harold Rosee Member ✭✭

    I use an AT-Auto plugged into my 6600M. Follows the radio nicely. Great tuner. If you look for one the newer ones have the grey push buttons on and the older ones are red.



  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator

    The latest had three grey and one red button. The power button is black with red trim and lettering. Also stenciling under mode button says Menu - push and hold.

    I received one of the last 5 manufactured by PalStar. I had an order for one through my local PalStar dealer and the owner was getting **** around by Paul @ PalStar. Finally after complaining to Paul his son Pete was selling them on eBay but they wouldn’t fulfill back orders, PalStar sent one to the dealer. Right after that the cease and desist order went into effect since Kessler Engineering won the patent lawsuit.

    Here is a picture on the one I had. This was the latest button, power switch, and stenciling configuration.


    Dave wo2x

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