Here's some stuff one can observe when no AGC interferes and the risk of a lightning hitting the (indoors) aerial is minimal. Actual I am reminded now that I had intentions to build some meteorological receivers...
Thunderstorm
This spectrum-image nicely shows the storm passing with a maximum intensity. Traces of QRSS signals in this spectrum.
Black clouds passing
These structures were seen in my spectrum receiver earlier. Honestly, they remained a mystery to me. That changed with today's observation however.
Sitting at my study's desk doing paperwork, the sky got extremely dark all of a sudden. Usually I have half an eye on the spectrum receivers, also today, with not much going on. Besides this:
In order to be able to compare the atmospheric stuff with man made signals, I temporarily changed SpectrumLab's settings to cover the 30m WSPR band. To me this result clearly shows that I am not looking at an ionospheric phenomenon.
The plan for the next front transient is to capture even wider spectra.