Passband & Noise Floor ?

SDRPlay Independent Community Forum Forums SDRUno Passband & Noise Floor ?

  • This topic has 5 replies, 3 voices, and was last updated by .
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  • #328
    Robert11
    Participant

    Hello,

    Using SDRUno and RSPdx.

    Is there any way to independently drag one one of the edges
    in the Passband as shown in the AUX SP window ?

    And, is -90 to perhaps -100 db a reasonable noise
    floor for am below 15 MHz ?

    #332
    SDRplay_Tech
    Participant

    The best thing to do in these circumstances is to post a screen shot so that people can see your noise floor and settings. Please note that SDRuno (unlike other SDR software) always shows power in dBm as referred to the antenna port and not dB or dBfs. Most other software uses dBfs (dB relative to the ADC full scale). When you refer to the noise floor, are you referring to the visual level as indicated on the spectrum display or that indicated by the power meter? They will be different (for very good reasons).

    SDRplay_Tech

    #334
    Robert11
    Participant

    Hi,

    Thanks for interest and help.
    Sure is a lot to know.

    a. I was eyeballing the baseline visually on the Spectrum display.
    I will try to attach the screenshot you requested.

    Does it look “reasonable” for the noise floor level ?
    (-95 to perhaps -120 seems “typical” for the sw bands <30 MHz that I usually see)

    One more question, please:

    b. Sometimes when I first start SDRUno, I cannot change any of the numbers
    on the RX Control screen using my mouse wheel. It does work after
    doing a start or two more, with shutdowns between.

    Is there any “trick” to always being able to use the Mouse wheel to change and
    enter numbers for the frequency ?

    Thanks,
    Bob

    Attachments:
    #336
    SDRplay_Tech
    Participant

    Hello Bob,
    Your noise floor does sound a bit high. Make sure your RF gain is as high as possible without getting an ADC overload warning. Also, disconnect your antenna and if your noise floor falls substantially then the noise problem is down to your antenna installation.

    Regarding your second question, the scroll wheel on your mouse will only change the frequency if you have selected either the Rx Control Panel the SP1 Panel or the Aux SP Panel. To check this look to see whether the SDRuno text at the top of the panel is red or not. If it is red, then it is selected or ‘in focus’.

    Regards

    SDRplay_Tech

    #338
    Robert11
    Participant

    Hello,

    Just a quick thanks.
    Appreciate the info.

    Regards,
    Bob

    #345
    Andy2
    Participant

    BTW Robert, if you want to drag just one side of the IF passband, hold CTL and drag the required side. It’s in the manual under ‘Asymmetrical passband’ somewhere.
    That noise my be coming from local VDSL cables, I get it here. Mine’s easy to spot, as there is a sudden ‘shelf’ of noise (rising about 10dB) at 8.5 MHz, which is where one of the VDSL bands begins.

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