GNC355 Weak Transmit

Discussion in 'Avionics and Upgrades' started by guzziguy, Sep 7, 2020.

  1. WDD

    WDD En-Route

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    Vintage Snazzy (so my adult children say)
    Thanks for posting. Just so I understand, it wasn't the coax cable your installer originally used. It was the Mic Gain setting, not the carrier squelch setting? And you're sending it back for warranty replacement because the software keeps flipping it back to the default -12?
     
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  2. AA5Bman

    AA5Bman Line Up and Wait

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    He who ironically no longer flies an AA5B
    This is about the most frustrating thing in aviation: go for an upgrade, end up chasing your tail and wasting tons of money and brain damage in the process. Been there, done that, it sucks. Hope you get it figured out.
     
  3. guzziguy

    guzziguy Pre-takeoff checklist

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    Yes, this is correct.

    Update:

    I contacted Garmin and they told me with my findings and they said that it sounded like a warranty issue. They asked that I go to a Garmin dealer, have them bench test it and then have them return the unit for warranty replacement.

    The avionics shop tested and DID observe the fact that the settings would revert back to the wrong settings. Garmin swapped it out for a new one and, so far, things seem to be working just fine.
     
  4. Christopher Kennedy

    Christopher Kennedy Filing Flight Plan

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    Lespaul
    I wonder if I could get the serial # of your old unit as I think Garmin may be reboxing and I may have a previously bad unit. My unit is intermittent also.
    Garmin is sending a new unit to my installer too.
    I hope this does the trick.
     
  5. guzziguy

    guzziguy Pre-takeoff checklist

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    The issue reappeared tonight! So, afterwards, I went into settings and set it to the known-good settings I sent you the pic of. We'll see if it holds.
    Unbelievable. I had to switch to my KX170b the volume was so bad through my mic.
    I have no idea what my SN was for the old unit (wouldn't that be something???)
     
  6. Seth Pierce

    Seth Pierce Filing Flight Plan

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    +1 for low transmit power on newly installed GNC355

    Comm 2 loud and clear
    New audio panel from ps engineering
    New antenna

    any news on this front?
     
  7. jd21476

    jd21476 Line Up and Wait

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    Im having this issue on my GNC355 that was installed a few months ago. I thought maybe it was an audio panel issue but I just had a new PSE 450b installed and it is still a problem. Ill check my mic gain.
     
  8. Jonathan Crisler

    Jonathan Crisler Filing Flight Plan

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    Has there been a fix to this issue. I have a GNC355 and Get Loud and Clear, and then out of know where no one can here me. What are the correct COM settings for this to work?
     
  9. jd21476

    jd21476 Line Up and Wait

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    This was the fix from my avionics installer and it worked fine.



    I called Garmin, and I think that it is the mic gain setting for the GNC 355. Since I will be off next week, I will walk you through the steps to adjust that.

    First, get into configuration mode, starting with the unit powered down.
    The Configuration mode of the GNC 355( ) can be accessed by holding down the inner knob located at the
    bottom-right of the unit and pressing the Power/Home button. When the Configuration mode home page displays, release the knob.

    From there you will see six tiles or buttons, select the Setup button. then select the COM button in the next menu.

    From here, select the Mic Gain Button which can go from -12dB to 30dB.
    This will adjust the gain of your microphone for your Com Tx. If it is too low, your transmit will be received quiet, if too high, then it will sound distorted.

    Please increase the gain as necessary.
    You will also see sidetone volume in that menu, you can adjust it if you feel that your sidetone is too loud when you transmit.