FTDX-3000 AM on 6 meters no audio, just carrier

Discussion in 'Ham Radio Discussions' started by KN4ROB, Apr 13, 2021.

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  1. KN4ROB

    KN4ROB Ham Member QRZ Page

    I'm a new'ish tech ham (wanting to get my general)
    Just picked up a DXFT-3000 at a local hamfest, my 1st HF radio
    I just worked a "testing" local net on 6 meters with attic dipole (1.2:1 SWR)
    53.770 FM 5W into repeater. feedback from net control , great signal, clear audio
    switch to
    50.250 SSB 30W , feedback from net control , great signal, clear audio
    then to
    50.400 AM 25W, feedback from net control , just carrier, no audio (I could hear net control and others just fine)
    Next day, went through all my Audio and AM settings, testing into a dummy load to an HT on 6 meters
    same thing, just carrier, maybe a crackle of audio, (monitor sounds good) 5W-25W power level testing
    so today, I tested AM on 40 meters into dummy load (I'm still just a tech, so no on air testing)
    HT had good audio on AM & SSB , so my issue is just 6 meters
    what am I missing ? looking for any suggestions to test/try .....
  2. WE4E

    WE4E Premium Subscriber QRZ Page

    Check menu 053 AM MIC SEL. You have the option for FRONT/DATA/USB. Make sure it's on FRONT. Current Yaesu radios have a habit of remembering different settings per band, and that might account for why it's only 6m. Does it happen on 10m?
    KQ9J likes this.
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Did you try a FULL RESET on the rig?

    Modulation is all done in DSP, including AM, and it's curious it works okay on SSB but not AM. Still, before trying any further de-bugging, I'd try the FULL RESET as instructed on Page 7 of the manual.
  4. KQ9J

    KQ9J Premium Subscriber QRZ Page

    That would do it.
  5. KN4ROB

    KN4ROB Ham Member QRZ Page

    Thanks for the quick answers
    Yes, I did a FULL factory RESET, when I 1st power it up from the hamfest (to be sure I didn't have any old setting in the radio)
    Menu 053 , it is set to FRONT , I changed it to USB, saved, and Back to FRONT then saved (just to be sure ;)
    all that was before I posted :(

    So I just hook my 200mhz scope to the dummy load, so I can see the signal @ 50.4
    Mic gain to 5 just carrier, mic gain to 100, lots of audio movement on the scope, HT was just noisy clicks
    so I've set the gain to 50, and (Menu 052) , and scope trace looks reasonable
    and the HT will feedback on the mic
    Hard to tell audio quality on HT as I'm speaking and listening at the same time

    it may be the mic itself, going to another hamfest this weekend, going to get a better mic anyway
    I've attached the trace of me saying "test" loud and slow (052 AM mic gain 50)

    Attached Files:

    W4NNF likes this.
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    So, it actually does work on AM!

    The scope trace looks like very weak modulation, though...25% or something.

    Wonder why it lacks modulation on 6m but not on other bands?

    Design flaw? I have no idea.

    There's not much AM on 6m nowadays anyway, but it would be interesting to find out why this is occurring.

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