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10M and 6M SSB audio "warbling"

wb7ond Member ✭✭
edited March 2020 in FLEX-6000 Signature Series
Due to the latest 10 and 6M band openings, it is the first time I tried ssb. I am having "warbling" rx/tx audio on 10 and 6M. After a search, I saw the thread "distorted audio on 6600" and K2RB's post at the end about the 10Mhz reference. This mirrors my symptoms. His solution of Auto only temporarily seemed to clear up the audio with the external reference disconnected. I use the external 10Mhz ref from Leo Bodnar's GPSDO on lowest amplitude setting about 1.2v p-p measured at radio connected through a 30' RG-174. I saw the spec (1 to 3v p-p sq wave) for the min and max amplitude. Its a "square wave" with no overshoot. The green check (locked) appears for ext ref in auto, and also if I pick ext ref manually, so I suspect the check is amplitude driven... I have tried all the combinations of auto, tcxo, ext ref, connecting the ref, disconnecting the ref. Cannot find the combination that reliably stops the warbling. I can select tcxo with no ref connected, and once in awhile it clears, so I reconnect the ext ref, pick auto, and the warble comes back. Then I go back to the tcxo with no ref, and still the warble is there. The green check seems to always come on, and it will sometimes go into search, and come back with the check. What causes the warbling audio with the external ref hooked up?


  • K3SF
    K3SF Member ✭✭
    edited March 2020
    there is nothing wrong with the radio

    what you are hearing is aurora induced Faraday rotation effect

  • Al K0VM
    Al K0VM Retired Member ✭✭✭
    edited July 2018
    May I suggest that it might be RF interfering with the 10mhz ref from the GPSDO into radio.. Try running on the internal reference… Does the warbling go away.?

    AL, K0VM
  • mikeatthebeach .
    mikeatthebeach . Member ✭✭
    edited July 2018
    Bug detected

    I had a problem with my Flex6600M with Tx/Rx Warbling ( Jitter ) after being ON for full week

    Detected Jitter - Warbling effect in Tx & Rx

    Thought it was a bad Internal Reference

    Solved it by downgrading from Version 2.3.9 to Version 2.3.7

    Next I Upgraded to from Version 2.3.7 back to Version 2.3.9

    Now have no Warbling - Not using External Reference

    It's worth to give it a try !

    73 Mike

  • K5XH
    K5XH Member ✭✭
    edited July 2018

    You didn't state if the problem was on transmit as well as receive.

    I was having a similar problem with my two month old 6600. I had raspy sounding audio on both transmit and receive. I first noticed it on 10M SSB and it was worse on 6M SSB. I actually thought it was aurora at first. In fact there was elevated geomagnetic activity at the time. But subsequent checking ruled that out. Flex identified a bad cap somewhere in the master oscillator circuit that was causing the problem.

    73, Mark

  • wb7ond
    wb7ond Member ✭✭
    edited July 2018
    Thanks for the replies.  I did have the problem on tx audio also.  Maybe I need to dispense with the external reference...  I sure do appreciate the responses..

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