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How do you connect an amplifier to the Flex-6500? I'm using an AL-811H

Hello, I am trying to get my AL-811H connected to the Flex 6500 however not able to get the radio to key the amp. Help?


  • John Betner
    John Betner Member
    edited September 2013
    Maybe this is just a **** question but I haven't been able to figure it out lol
  • George KF2T
    George KF2T Member ✭✭✭
    edited February 2019
    There is an RCA jack (actually 3) on the rear panel that serve as relay outputs to switch external devices, like amplifiers. Connect to the PTT in on your amp, and you'll be good. One warning, make sure the voltage and current you're switching is within the range the relay will handle, especially if your amp has a mechanical relay that might "feature" a voltage spike from th coil.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    Also set up the TX Relay parameters in Radio Setup->Transmit for your radio too.
  • Ed baker
    Ed baker Member ✭✭
    edited September 2016
    the transmit set up : Thanks Tim
  • Bob G   W1GLV
    Bob G W1GLV Member ✭✭
    edited June 2020
    John , the best way to connect the Ameritron 811H is to use a rig buffer like the Ameritron ARB-704. The amplier you are using is a tube job, the transmitter is an expensive transistorized transceiver. For 60 bucks you can't go wrong. Follow the instructions from Ameritron and you will be good to go.
  • Ed baker
    Ed baker Member ✭✭
    edited September 2016
    You really should be reading the MANUAL 811H PDF pages 2, and 5. In the Amp instructions there is your answer The keying circuit is 12DC @ .100 ma .
  • VE2MBT
    VE2MBT Member
    edited November 2019

    For MINE, i use the Heil FS-2 for the EXACT same set-up, there is 2 wire on the pedal, 1 for the amp, 1 for the radio.  The pedal KEY the Ameritron few milisecond BEFORE it key the radio !!!, this also permit the use of the TUNE BUTTON on the flex without keying the amp. so my LDG automatic tuner work at low power, when antennas is tuned, you just press the pedal and adjust the load and plate of the amp. few second later you are good to go :-)

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