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How do I turn on/off APF in V1.13

W5UN_Dave Member ✭✭
edited May 2020 in SmartSDR for Windows
I am looking for documentation concerning the APF. Where do I turn it on or off, or set it's width?


  • Stu Phillips - K6TU
    Stu Phillips - K6TU Member ✭✭
    edited May 2020

    The control is only accessible in CW slices...

    It replaces ANF in the DSP controls both in the Slice detail panel at the side and the flag panel.  The flag panel has a slider where the APF gain can be adjusted.

    Stu K6TU

  • Robert -- N5IKD
    Robert -- N5IKD Member ✭✭
    edited March 2015
    Here is a picture.
  • Ernest - W4EG
    Ernest - W4EG Member ✭✭
    edited October 2019

    Robert - N5IKD,

    I love your answers!

    The photos are worth a thousand words.  Please keep them coming...

  • Robert -- N5IKD
    Robert -- N5IKD Member ✭✭
    edited March 2015
    I do like pictures and videos, they can tell a lot more than the author originally intends. 

    I also understand Dave's question, as I had the same question when I first looked for the APF in 1.1.3.
  • Dale W4AEJ
    Dale W4AEJ Member
    edited February 2014

    Flex 6500 with SmartSDR 1.1.3, Win7 Pro 64 bit.  

    On my setup the APF slider does not appear to adjust the gain of the APF, but instead varies the bandwidth. 

    I can verify this by watching the audio spectrum in MixW.  As I move the slider to the right the bandwidth decreases.  When I do that I also note that CW signals start to ring quite a bit.  The audio peak does not change.

    I have done a cold boot of the radio to ensure everything has been re-initialized. 

    Is my setup operating differently than intended?

    Thank you and 73

    Dale W4AEJ

  • Al_NN4ZZ
    Al_NN4ZZ Member ✭✭✭
    edited February 2019
    The slider adjusts the APF bandwidth in this version but changes are coming.  

    Check out this link, details there, it also addresses the ringing. 


    Regards, Al / NN4ZZ  
    al (at) nn4zz (dot) com
  • W5UN_Dave
    W5UN_Dave Member ✭✭
    edited November 2016
    Go back to the previous version of APF. This new one is awful. The previous version of APF worked nicely. (don't fix it if it ain't broke)
  • Dale W4AEJ
    Dale W4AEJ Member
    edited March 2014

    Flex 6500, SmartSDR, Win 7 Pro 64 Bit

    While I normally use DAX, I still have the rear panel audio connected to my computer.   Today I switched my audio source from DAX audio to the rear panel audio (pin 2 on the 15 pin connector), and was surprised to see that, when running in USB mode, the CW APF still appears to be active.

    I can move the peak around by switching to CW mode, changing the CW pitch, then switching back to USB mode.

    Here is a view, in USB mode, with the CW pitch set to 2,000 Hz:

    Here is the same view, also in USB mode, with the CW pitch set to 800 Hz:

    I do not see these peaks when using DAX.

    APF operates normally when in CW mode.

    The release notes for 1.1.3 indicate that APF is no longer active in SSB modes. 

    This is not really an issue as I normally use DAX, but an observation.  Is this unique to my setup, or has anyone else noted this?  I haven't seen anyone else bring this up for this version, unless my search missed it.

    Thank you and 73,



  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    You need to clear your persistence database, as APF was probably on when you had SSB selected prior to the v1.1.3 upgrade and now that the controls are CW specific, there is no way to turn it off.

    To clear the persistence DB, power off the radio.  Press and hold the OK button while momentarily pressing the power button to turn on the radio.  Continue holding the OK button until the console display counts down to 1 and the "Calibrating..." message is displayed on the front console, then release.

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