Local noise elimination

Dave · February 2023

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 · February 2023

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 · February 2023

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

Dan, we hear you. Every time.

Dan Trainor · February 2023

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

VE7ATJ_Don · February 2023

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 · February 2023

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 · 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.

James

WD5GWY

Local noise elimination

Active · Last Updated February 2023

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