Youssef the author of SDR# has recently released an update which adds a feature called "Sharp Slicer". This feature allows Airspy SDR users to open multiple instances of SDR#, each able to tune to a seperate signal within the currently tuned frequency range of the SDR. This is somewhat similar to the old multi-VFO plugin from rtl-sdr.ru, however the advantage of Slicer is that you can have seperate spectrum and waterfall graphs for each signal. This could be especially useful for monitoring multiple narrowband HF modes with an Airspy HF+ Discovery.
To use Sharp Slicer you must have an Airspy SDR, be it an Airspy Mini/R2 or HF+/Discovery. Unfortunately it will not work with RTL-SDR or other SDRs. Once the SDR is running in SDR#, simply press the "+" button on the top left to open a new Slicer instance. It seems possible to open as many instances as you want, and probably the only limitation is your CPU. On our Intel i7-6700 we tested up to 8 instances running at the maximum bandwidth of an Airspy Mini, and the SDR# CPU utilization was only at 50%.
A nice touch is that you can also see the location of each VFO on the master SDR# instance, and the color can be changed on each Slicer instance.
Over on Twitter @ea3ibc has also been testing:
Wow it's crazy!! SDR# Sharp Slicer with a single Airspy R2 device, excellent WFM with multiple instances. Great bandwidth! pic.twitter.com/WEeLhTshgj— EA3IBC Oscar (@ea3ibc) September 16, 2020
Awesome! SDR# Sharp Slicer.— EA3IBC Oscar (@ea3ibc) September 15, 2020
The best day since the covid pandemic started. Multiple instances of SDR# running under a single Airspy device.
SDR# 17.42 + Airspy Discovery HF + Youloop inside the house.
I need a wider screen. pic.twitter.com/1mqDbZCgQe