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How to enable noise floor scaling

K1FR
K1FR Member ✭✭
in SmartSDR+

Probably cockpit error on my part, but I am not seeing a way to enable this feature. Just updated to 4.1.3 on my 6700. Was expecting to see a menu item in the "Display" tab on the panadapter. Appreciate a hint on this. The new noise filter options are working fine. Thanks!

73, Tom

K1FR

Best Answer

  • Rich M5RIC
    Rich M5RIC Member ✭✭✭
    edited December 2025 Answer ✓

    Hi Tom

    This is only available for 8000 series and Aurora radios so guessing that's why nothing appears for the 6700.

    image.png

Answers

  • K1FR
    K1FR Member ✭✭

    Thanks, Rich! I missed that totally. 73, Tom

  • K1UO Larry
    K1UO Larry Member ✭✭✭

    BUT, if you did have that feature it couod be enabled and adjusted in the DISPLAY tab on left side of the SSDR screen.

    Personally I just grab the right side of the waterfall screen with a left mouse click and drag the noise floor to where I like it. I like to leave it up a bit in the waterfall display to allow for 3 levels of spots to display. :))

    YMMV. Happy Holidays de K1UO Larry

  • Erik Carling EI4KF
    Erik Carling EI4KF Member ✭✭✭✭

    If you have SDC, you can have this on any Flex radio. Also, the implementation and effectiveness is superior to that in SSDR.

    SDC_n6k0QOqYqg.png
  • Sergey KN7K
    Sergey KN7K Member ✭✭✭

    Hi Eric, did you find AGC threshold is a good value? It is about 40+ on AGC-T that I find a bit high. I am using AGC threshold around 23-27, that is about 30 on AGC-T.

    Sergey

  • Erik Carling EI4KF
    Erik Carling EI4KF Member ✭✭✭✭

    Hello Sergey

    It will depend on your receive environment.

    I went through the Flex tutorial to find the optimum RF Gain for each band. This is important because if you have this wrong, an incorrect AGC-T will ensue. Then I checked manually for the optimum AGC-T and came to a setting of 6 dB in SDC that set AGC-T to around 50 for every band. I checked manually if adjusting AGC-T from the SDC calculated value was better or worse but actually is was spot on in my case.

    So now I don't have to consider AGC-T at all. I change bands, SDC recalculates and I get the optimum receiver performance in all cases.

    The more noise you have, the likelihood is that AGC-T will be calculated at a lower value because you only want gain on signals and not on noise (which you know). A common error, not saying this is your case, is to set RF Gain too high. AGC-T reduces to compensate but in this scenario I feel that receiver performance is compromised. I'm no expert, many will have opposite opinions, just that this is what I find in my environment.

  • Sergey KN7K
    Sergey KN7K Member ✭✭✭

    Thank you Eric, I just updated to Ver 19.03 and missed "Auto RF Gain Control" option.

    Generally at my location i tested AGC-T for a long time and optimal is about 30 for most of the bands and it will correspond with SDC AGC threshold around 23. But I need to play with that more for sure.

    73! Sergey

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