I'm monitoring web SDR just to see what's happening on 80m.  I just watched a little bump race across the spectrum, left to right. When it passed, there were several lines cutting across the waterfall. What causes that?

Ionosonde

Thanks. I hadn't heard of that before.

Not as fun as alien first contact, but informative.

FPNI.

Cool video of tracking on ionosonde through the bands:

Here is a link to the Global Ionosphere Radio Observatory,  you can see the real time ionograms from some of these chirpsounders.

Home page:

https://giro.uml.edu/

Ionogram thumbnail page:

https://giro.uml.edu/IonogramMovies/

Please note that you can use a ionosound in both the vertical mode (most scientists) or in the oblique mode, (Hams and Military) VERY useful if you can  track a sender near the other end of your link.- makes picking the "best" frequency idiot proof.

Rege