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fldigi's waterfall has no relationship with the vfo

Discussion in 'Software Defined Radio (SDR)' started by KD0UCA, Mar 22, 2020.

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  1. KD0UCA

    KD0UCA Ham Member QRZ Page

    I'm new to CAT control, so apologies for what may be a simple fix.

    I have a FT-991A connected to a computer via USB cable only.

    I'm able to play with the VFO on flrig, and see the change on the physical radio. I'm also able to spin the physical VFO knob on the radio, and see it reflected on the software.

    My understanding of fldigi documentation is that the waterfall is the best way of tuning to wherever. However, the waterfall seems to be totally off base with where my VFO, flrig, and fldigi says I am.

    What simple little thing am I missing?

    Attached Files:

  2. AF9US

    AF9US Ham Member QRZ Page


    It appears from your description that the audio input to fldigi is coming from some other source than your FT-991A. Most likely, the audio input is from the built-in microphone on your computer. One way to verify is to make a noise, either by talking or making a loud noise near your computer. If the audio input to fldigi is coming from the computer microphone, you'll see the noise, you just made, reflected in the waterfall display in fldigi.

    The fix requires you to go into fldigi Configure menu, select the Soundcard, then Devices. Most likely, the USB Audio CODEC is what you should choose for Capture and Playback in the Port Audio box. Port Audio should be checked, I believe Port Audio is checked by default.

    Save the newly configured Soundcard settings (Configure Menu, then click Save Config). Exit flrig and fldigi, then restart both programs.

    Good luck!
    Bernie, AF9US
  3. KD0UCA

    KD0UCA Ham Member QRZ Page

    Thank you much for the reply.

    The computer is currently a RasPi, and as such doesn't have a microphone. Also, I wanted to say again that I can control VFO, RF power using each of fldigi, flrig, and physical radio, and the other things reflect the change within a moment. The waterfall however remains somewhere out of band lower than 160M

    To be fair, I looked again in the rig settings of both fldigi and flrig to verify that it was using USB sound card.

    It appears to me that the soundcard settings are correct. Observing how changing software on the computer makes changes on the physical radio screen, and same vice versa, confirms to me that the radio and computer do have 2 way communication between them.

    For whatever reason though, the waterfall/scope of fldigi seems to be rouge and somehow not on par with everything else. Looking at the original picture again, there are clearly signals on the scope as opposed to just white noise.
  4. KC2RGW

    KC2RGW Premium Subscriber QRZ Page

    To AF9USs point, it's almost certainly the wrong sound device. If flrig and fldigi frequencies all align as you tune the radio and those signals are not moving left to right as you tune, it's not listening to your radio. Either wrong sound device or the radio itself if not sending the data/audio over USB to the device you have selected.

    Your COM port is correct for CAT but the USB data/sound is not set up right. I attached an image of what the sound device from a IC-9700 looks like in fldigi on a Debian linux system.

    Attached Files:

  5. AF9US

    AF9US Ham Member QRZ Page


    Check the menu selections in the FT-991A. Verify the radio-audio is programmed to go out the USB port (on the radio) rather than the Data port(on the radio).

    Bernie, AF9US
  6. KD0UCA

    KD0UCA Ham Member QRZ Page

    I can't write enough expletives to convey the frustration.

    I've tried on a different computer with the exact same results.

    I see that it's pulling out actual cw qso's and printing them to screen.

    This flipping scope that were supposed to be able to tune with is a serious issue.

    As far as radio menu settings, I came across "ft991 USB FLDIGI WSJTX all menu settings" and made sure I matched exactly.

    The webpage comes up with near identical settings.

    But wait... There's hope!
    I'm looking at the fldigi manual more, and I'm noticing in pictures that the scale above the waterfall never matches the frequency up top. Kinda makes me wonder if I've been chasing a shadow

    Maybe I just need to ignore those numbers altogether?
  7. K3RLD

    K3RLD Ham Member QRZ Page

    The waterfall shown in FLDigi is only a tiny little sliver of what is shown on your 991 waterfall.

    [edit] and the "frequency" of the waterfall in FLDigi is the "audio frequency" corresponding to the small sliver of actual RF frequency.
    KA9JLM likes this.
  8. KD0UCA

    KD0UCA Ham Member QRZ Page


    Thank you very much for the info! I feel like it confirmed my suspicion that nothing was actually wrong at all.

    Further, you told me why it's like that, which helps me understand the whole computer/radio thing that I'm obviously just now getting into.

    Thanks again!

    73, Brad
    KA9JLM likes this.
  9. N2OG

    N2OG XML Subscriber QRZ Page


    FOR FT8 try this adjust the Cursor Frequency in the window below the waterfall on the main screen to 1500. And adjust in your FT-991A menus 64 and 65 to 1500 Hz.

    For RTTY set Cursor to 2125 and menus 64 and 65 to 2120

    for CW set Cursor frequency to 800 and menus 64 and 65 to 800

    each mode is different so you have to play with offsets to get it straight.

    Good Luck KN4SMO Scott
  10. KC2RGW

    KC2RGW Premium Subscriber QRZ Page

    Just reread may be misunderstanding a dynamic here.

    if you are tuned to say 14.070 USB on the rig, the waterfall shows roughly the 3kHz passband being received. You can click the filter in fldigi to decode anything in that passband.

    if you click on that waterfall in fldigi, it just puts the filter on that spot in the pass band (the frequency offset in the passband), it doesn’t tune the radio. Now, if you click and you want it centered, if you hit the QSY button in fldigi it will tune so the signal is now centered on where you have the “sweet spot” configured. Typically that is 1kHz or 1500Hz.

    Tune the frequency to shift the passband you are receiving, click in the waterfall to put the decoder filter on the signal you want to read within that passband.

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