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Flex 6500 with Elecraft KPA-500/KAT-500 setup

Hey all

I just took possession of a used Elecraft power combo. I've got it all wired up including the Flex to amp cable. Anyway, the amp sees the Flex and changes bands and the tuner sees the Flex and changes antenna ports as needed.

I've got the amp in operate and when I key the radio I get nothing. No SWR or power led's turn on. The amp isn't showing any faults either.

I did reset the amp to default values and then set it up per their instructions for the Flex. The Flex 6500 is seeing the new cables and has been configured per Elecraft's instructions.

Any ideas where to go from here? I'm pretty sure it's user error and not faulty equipment.

Thanks in advance and 73's




  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Jeff, do you have a cable from the TX port to the PTT of the Amp? You also need to be sure that it is "on" using the TX Band Settings screen:

    I have a 6400, so I have TX1, TX2 and TX3 that I can use. I don't know how many TX jacks the 6500 has, so you may need to adjust based on that.

    I also have the KPA500 / KAT500 combo, and I run TX1 to one of the tuner PTT PLY jacks and from the other jack to the PTT jack on the amp. This is done to keep from keying the amp under certain conditions.

  • KG9LD
    KG9LD Member ✭✭

    Hi Len

    Thanks for replying. I have it set up the way you do. I am running the Mac version on SSDR but I don't think that makes a difference. I'm still checking everything to make sure I have it wired correctly.

  • KG9LD
    KG9LD Member ✭✭

    Well, I fixed the problem and I'm pretty darn embarrassed...

    I ran coax from Ant 1 into the amp and totally forgot to set the radio to tx on Ant 1.

    Thanks Len lol

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    I'm glad that you got it figured out! I really like my FlexiCraft station, I think you will too.

  • KG9LD
    KG9LD Member ✭✭

    So far.... I do. Thanks again Len

    Jeff KG9LD

  • w1smc
    w1smc Member ✭✭
    edited September 2021
    I will be getting my 6600M tomorrow and will be connecting my KPA500 sometime this weekend. What are either of you using for settings for the amp on the Transmit Tab in the Main Menu?
  • KG9LD
    KG9LD Member ✭✭

    I own the Flex cable that Elecraft sells. With it, it is seamless and fully automatic.

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    The setup is pretty simple and described in the USB Device Document. https://www.flexradio.com/documentation/usb-cable-interface-guide-pdf/

    Make sure the baud rates match.