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Are you getting the best receiver performance out of your FLEX-6000?

Tim - W4TME
Tim - W4TME Administrator, FlexRadio Employee admin
edited May 2020 in New Ideas
In order to get the best receiver performance out of your radio, you have to optimize the signal to noise ratio (SNR) based on band conditions and the ambient noise that your receive antenna is picking up.  Optimizing the receiver SNR is a fairly straightforward thing to do and it is done by making sure you have the RF preamp set correctly and, this is the real important part, you have the AGC set properly.  Properly adjusting the AGC is done by using the AGC-T control, which is an often overlooked feature in SmartSDR, but the most powerful one for mitigating noise and optimizing the receiver SNR.

A detailed description of how the AGC in SmartSDR works and even more importantly, how to properly set it is covered in the updated HeldDesk article How does the Automatic Gain Control (AGC) work in SmartSDR.

I highly recommend taking a look at this article as a properly configured AGC can make the difference between getting that weak on in the log or not.


  • Neal_K3NC
    Neal_K3NC Member ✭✭
    edited March 2020
    Another great article from the Hardest Working Man in Customer Experience!! Thanks you wooly bear you!
  • tparish
    tparish Member ✭✭
    edited March 2020
    THANK YOU TIM! I am so grateful for this. I've had my Flex about 9 months and love it. But I admit I'm not up to speed on how best to adjust my 6400M for best receiver performance. This came at just the right time.
    Tom KB5RF
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited March 2020
    That's my boy!  :)  This is awesome Tim.
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited March 2020
    A very important article Tim. I always felt that the AGC-T is the least understood feature in SSDR.
  • HCampbell  WB4IVF
    HCampbell WB4IVF Member ✭✭
    edited March 2020

    Agree that the AGC-T control is a very useful Flex feature.  Hope that there will be follow-on improvements such as an option for automated AGC-T, or at least a visual display of the AGC-T setting.

  • Santiago Mejia HI8O
    Santiago Mejia HI8O Member ✭✭
    edited March 2020
    Thanks Tim, as a new user (8 months) this article is invaluable.
  • Wilbur Doolittle
    Wilbur Doolittle Member ✭✭
    edited March 2020
    Is there a you tube on this?
  • Neil D Friedman N3DF
    Neil D Friedman N3DF Member ✭✭✭✭
    edited March 2020
    In FT8 mode, I set the AGC-T so that FT-8's green thermometer reads about 30 on a quiet band.  I set the AGC speed setting to "off."  Is this speed setting correct?
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2020
    Good question. The answer is "it depends".  Setting the AGC to OFF turns off the AGC algorithm altogether so you have to be careful about how you set the AGC-T so that you are not adding too much fixed gain to the recovered audio.  Using SLOW enables the AGC algorithm and can be beneficial to reduce the volume when there is external short-lived noise sources such as lightning crashes.
  • Sergey R5AU
    Sergey R5AU Member ✭✭
    edited March 2020
    Neil, SDR provide high passband dynamic range and better do not use AGC at all with digital mods but utilize necessary filters for station selection. My AGC-T n Digi usually within 10-15 points without overloading receiver
  • Keith WA0BEU
    Keith WA0BEU Member ✭✭

    Thanks Tim, Great article!!!

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