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Connect Flex 6400 to ALS 600

Terry L Angle
Terry L Angle Member ✭✭

I just bought a used ALS 600 w/ power supply. My 6400M has auto tuner built in. I want to connect the amp so it will auto change bands when I change bands from the radio.

I have read older discussions about how different ones have connected the radio to the amp. None of them stated they had radio auto tuner. They also stated MFJ items to use. If I need something from MFJ please let me know what would work best.



  • AA5NM
    AA5NM Member ✭✭

    Well, seems not to have stirred up much interest in a year plus. would you post something heere if you solved that problem and if not, let me know.

  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator
    edited November 2022

    I had answered the question in the ALS1300 to 6400 thread. Here’s the steps

    • you do not use the internal antenna tuner on the radio
    • you will need the ARI-500 interface from MFJ RJ-DB97DK
    • you will need a USB to serial cable with an FTDI chipset which plugs into the USB on Flex to the MFJ cable’s DB9 connector
    • the MFJ RCA connects to the Flex TX1 output
    • You need to program the USB to serial cable as a CAT cable in the Flex. See https://www.flexradio.com/documentation/usb-cable-interface-guide-pdf/
    • Do not use the DIN connector on MFJ cable
    • if your antennas have a high SWR, you will need an external antenna tuner between the amp and antenna


    Dave wo2x

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