I am trying to get my AL-811H connected to the Flex 6500 however not able to get the radio to key the amp.
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 :-)