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FT8 transmitted signal

Erik Carling EI4KF
Erik Carling EI4KF Member ✭✭✭

I have just acquired a new 6400M. My first venture with it is FT8. On transmission I am rather alarmed to see this:

I have all these side bands either side of the transmitted signal. For the life of me I cannot work out what I have done wrong. Can anyone help please? Thanks Erik EI4KF.


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

    You need to show a screen shot with the measurement points on the right side of the graph.

    If you are zoomed in, this could be a normal view especially if you are showing down to -120.

  • Erik Carling EI4KF
    Erik Carling EI4KF Member ✭✭✭

    Hello Mike.

    The TX Gain is at 45 and the Level Meter shows about -8. Is it ok or am I transmitting a bad signal, which is my concern?

    Thanks de Erik.

  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator

    Hard to tell without picture of whole SmartSDR screen but judging from your first picture and then second picture the primary signal is more than 60 dB above the other “peaks”. This does not reflect your actual transmitted signal out over the air but based on what I am seeing it looks normal.

    you could look at your signal over the air using a web SWR receiver or ask someone with a Flex to do a screenshot of your signal.

    Dave wo2x

  • Erik Carling EI4KF
    Erik Carling EI4KF Member ✭✭✭

    Thank you Dave. I have managed to improve it, not sure how except I did a reboot. I can see that you are right and it is not being transmitted.

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