NB (noise blanker) functionality on GQRX running on Mac with Airspy HF+

[John Isella]

Hi All, I'm running GQRX version 2.16 on Mac OS Ventura with an Airspy HF+ via USB locally on the computer. All works very nicely except the NB selections and values don't appear to have any impact on operation at all. I'm not sure if there should be noise reduction as a function of these selections, but it would certainly be useful since there is a lot of "white" noise on received signals that seems like it would benefit from some DSP noise reduction. Thanks for any replies. John K1KSC

[righthal...@gmail.com]

I am running gqrx 2.15.9 on MacOS Monterey and I see the same thing - no difference with the settings between 0-20. When the program does the down convert between 7MHZ and 10 KHZ there are several stages of noise reduction. Perhaps most of the noise has already been removed. Other programs do the down convert with little to no noise reduction - with them the noise reduction works dramatically. gqrx is doing something strange behind the curtain - when I change the Bandwidth, it has no effect on the amount of noise. With SdrGlut when I switch from AM to Narrow band AM there is a Large reduction in the noise - as expected.