Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

Flex 6400 (not M) RX A doesn't work


Apart from selecting RX A as input in the VFO slice, is there any other thing I need to do to activate the receive antenna input? At the moment, it doesn't work...

Thanks and 73.



  • John KB4DU
    John KB4DU Member ✭✭✭✭

    Well Pete, it works for me just as you expect. I have a loop-on-ground low noise receive antenna for 40M connected to the RX In on the 6400. When l select RX A in the slice, I get the receive antenna without doing anything else.

  • Ted S
    Ted S Member ✭✭

    If you listen carefully when you switch the RX ANT from the same antenna you use for transmitting (ANT1/ANT2) to RXA you will here a relay click and if nothing is connected to the RXA jack the noise floor will drop. Also note that you only have one SCU so both Slices will change to RXA whenever you select RXA from either slice. You can also connect a RX antenna to the XVTA jack, just be aware the XVTA jack is also a low level output and can be selected as a TX antenna with a low level output signal ~ 0 to +15 dBm on your TX frequency.

    73, Ted WR4T

  • Pete Parisetti
    Pete Parisetti Member ✭✭
    edited September 2021

    Thanks for your time, John and Ted. The problem went away with a factory reset. 73 Pete

Leave a Comment

Rich Text Editor. To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph. An inline formatting menu will show up when you select text. Hit tab to get into that menu. Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.