It's all about the Software

SDR-Console has a weird bug with any AIRSPY HF+ (Discovery or dual port) that doesn't happen with SDR#.
I can't receive anything within a few MHz of 20MHz unless I reduce the sample rate to 384kHz.
At 768kHz when tuning within 2 or 3 MHz of 20MHz there is just nothing, not even a noise floor.
It's like SDR-Console sees something in the signal and shuts it off after a fraction of a second.
If I flip the pre-amp on and off I can sometimes get a burst of noise.
There are also regions on the fringes of the area around 20MHz where I can hear intermittent bursts of noise where it starts and then cuts off over and over.
Reduce the sample rate and the problem goes away and I can receive fine.
No sign of any similar effect in SDR#.
However I hate SDR# since it's full of annoying smaller bugs where changing one setting messes up another until you stop and restart receiving.

BrianG61UK wrote: Mon Feb 14, 2022 1:27 pm It's like SDR-Console sees something in the signal and shuts it off after a fraction of a second.
If I flip the pre-amp on and off I can sometimes get a burst of noise.
There are also regions on the fringes of the area around 20MHz where I can hear intermittent bursts of noise where it starts and then cuts off over and over.

To me this sounds like you have a very strong local signal somewhere near 20MHz triggering Auto-Mute. Make sure you have this unticked? Has caught me in exactly the same way due to local MF transmitter. So my guess is reducing the bandwidth excludes the offending signal from the passband?

https://www.sdr-radio.com/wideband-dsp
Max

I have to turn on the pre-amp when using my Airspy HF Discoveries on 20m and higher. OTW I get a 0 noise floor and pops and crackles sounds in the audio. Once the pre-amp is on, the noise floor rises, and audio returns to the normal static sounds.

73 Kriss KA1GJU

Max wrote: Tue Feb 15, 2022 11:39 amTo me this sounds like you have a very strong local signal somewhere near 20MHz triggering Auto-Mute. Make sure you have this unticked? Has caught me in exactly the same way due to local MF transmitter. So my guess is reducing the bandwidth excludes the offending signal from the passband?

Thank you for pointing me to the right area.

It was actually the noise blanker rather than the auto muting.

If I turn off the noise blanker, everything is working as it should.

BrianG61UK wrote: Wed Feb 16, 2022 2:15 pm

Max wrote: Tue Feb 15, 2022 11:39 amTo me this sounds like you have a very strong local signal somewhere near 20MHz triggering Auto-Mute. Make sure you have this unticked? Has caught me in exactly the same way due to local MF transmitter. So my guess is reducing the bandwidth excludes the offending signal from the passband?

Thank you for pointing me to the right area. It was actually the noise blanker rather than the auto muting. If I turn off the noise blanker, everything is working as it should.

Thanks for letting us know. Useful for future reference of other users.

Max