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.

2nd harmonic detected

Using the Flex6400M and V3.7.3

While calling cq in cw on 3.545 MHz , I saw my call be monitored by a cluster on 7.085 MHz.

Checking with the second VFO I found out that the signal on the second harmonic was strong enough to be detected by other stations over Europe.

I never have had this prior to the last update to v3.7.3

I wonder if any one has the same problem.




  • Erik Carling EI4KF
    Erik Carling EI4KF Member ✭✭✭
    edited February 22

    After making the upgrade to 3.7.3, did you “Cold Boot” your Flex? I omitted this requirement even though I had read the release notes and had exactly the same issue except I was on 1.830 (calling 8R7X) and was reported on 3.660. I also had strange TX on FT8 like there were many harmonics. I was worried! After properly completing the update, no such issues and the radio is again perfect.

    If you did cold boot, and still have the problem, notwithstanding any insights posted here I would open a Help Desk ticket.

  • Didier F6DXE
    Didier F6DXE Member ✭✭

    Thank yo as I indeed forgot to do a cold boot.

    I tried this without luck so went down one version , did a cold boot, re-installed the latest version, did a cold boot but the problem is still there.

    It seems to affect all bands at exact twice the base frequency.

    I will contact the help desk.


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.