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No power out on ssb

I have a 6400M with a power / audio issue. On ssb, I get no power out unless I turn mic gain way up to about 65 or so. The audio will be distorted and very low power while turning up the mic gain until I hit about 60 to 65 then power will jump up. Microphone is PR 781. I tried the FHM2 and no audio out at all even with mic gain up to 65. There is AM carrier and power on FM but audio is distorted.

I think it needs service!


  • VE7ATJ_Don
    VE7ATJ_Don Member ✭✭✭
    edited September 9

    HI Rick.... Under Settings (in SmartSDR) , on the Radio Setup tab, do you have the +20db toggle on? Does this make a difference? I don't know the PR781, but does it maybe need the Bias toggle as well?

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

    The 781 does not need bias but will require 20 dB boost.

    Watch the level meter to the right of the bar graph is a single little rectangle that moves up and down with level it is the paeak indicator if you use the internal EQ adjust level so peak indicator is around -10.

    also turn on OROC on main screen and set to DX position. If you are using the front panel display on 6400M it is in the menu by pressing the mic gain knob in. Also disable the DEXP (downward expander) which if enabled and too high can cause choppiness and distortion.

    Check out the YouTube video from Ken NM9P on how you can use full duplex to monitor what your actually sound like going out over the air,


    Dave wo2x

  • John KB4DU
    John KB4DU Member ✭✭✭✭

    Also, be aware the eq settings are after the level meter, so any eq boost can push the lever higher than indicated by the meter, so cut before boost. Generally, freqs below 400 should be cut as well above 3000.

  • Rick  WN2C
    Rick WN2C Member ✭✭

    Thanks to Ken Wells at Flex. He suggested that I download version 2.10.0 and it seems to have taken care of the problem. The audio was great with the FHM 2 microphone. Now I have to check with the PR 781. This audio issue was something that happened over night. One night it was working, next night not. Amazing what a software upgrade will do!

    Thanks Ken!

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