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Local noise elimination

Dave Member ✭✭

5 votes

Active · Last Updated


  • Dave
    Dave Member ✭✭

    Cannot remember where the idea came from and I have no idea if it's possible. First manufacture to work this our will own the market.

    Radio has a an extra antenna input back of radio for local RX antenna only. Maybe small loop ?

    Local signals picked up from antenna fed into SDR. SDR knows that they are unwanted signals

    SDR removes local signals giving clean noise floor. I understand noise comes from many sources and distance but having the ability to have some control and a chance to clean the noise floor even by 10 - 20% would make a massive difference.

  • Dan Trainor
    Dan Trainor Member ✭✭✭

    This is called Diversity Noise Canceling capability. Many receivers now have this including low cost ones like SDRPlay RSPDuo. Basically you set up a local noise capture RX antenna and the radio provides a means to phase the signals and noise from RX noise capture antenna with the main TX/RX antenna or another RX antenna. Most implementations use a circular dial type GUI control that you can manipulate both phase angle and magnitude between the two received signals and noise. This is the current state of art. Unfortunately for Flex users, Flex is way behind the curve and do not yet provide this noise cancelling function.

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    It is also called Noise Subtraction. Thanks for your input Dave.

    Dan, we hear you. Every time.

  • Dan Trainor
    Dan Trainor Member ✭✭✭

    Thanks Mike. Yes, basic noise subtraction function. Thank you.

  • VE7ATJ_Don
    VE7ATJ_Don Member ✭✭✭

    I wonder if it might be possible to add in noise cancelling functionality similar to the MFJ-1025 (or similar from other manufacturers) using the second antenna input.

    Maybe just reconfiguring some of the available processors in the FPGA's???

  • Rick_KJ5WO
    Rick_KJ5WO Member ✭✭

    Please!!!! Living in an Urban environment as many of us do could really use noise subtraction. I use a Timewave ANC-4 and it helps, but it's manual, so it must be tweaked every time you change bands and so on. It also works across all the spectrum at once, versus targeting specific noise birdies etc. The diversity mode included in the Flex is nice and adds another dimension to what we hear, but for my money dealing with noise is a bigger priority.

    Thanks Dave for bringing it up!

  • Trucker
    Trucker Member ✭✭✭
    edited February 2023

    Dual receivers ( physical, not virtual) are needed for Diversity Reception and Phase Cancelation which is only partially implemented in SmartSDR for the 6600/M and 6700. Currently only Diversity Reception is implemented. In PowerSDR using a Flex 5000A with dual receivers, Phase Cancelation works great. From what I can gather there is no way with a single SCU radio to implement this. Any Flex Radio that does not have dual SCU's cannot do this as you cannot physically connect two ,physically different antennas to two virtual receivers. On the non dual SCU receivers only one antenna can be used at the same time .

    It's all about the hardware.



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