WSPR
A quick and interesting video on QRP protocol WSPR.
As a dedicated Weak Signal Propagation Reporting network WSPR is also a way for those in poor locations to see where their signals can get and for those in better locations to paint the world with 20mW. For me it’s about optimising my antennas for my poor location and the challenge of building a dedicated high reliability WSPR transceiver but there are many other angles on this.

The WSPR protocol sends 162 characters of error corrected message using a 4 tone modulation system, and with narrow bandwidth and precise timing in 2 minute slots helping the de-coder find the signals deep in the noise.
Many Bands have a dedicated ‘quiet’ WSPR segment although there are the usual idiots on top now and then
You can check your results (example WSPR station: G8MCD) at http://wspr.rocks/ at any time and you can also upload what YOU are hearing with a software decoder https://wsjt.sourceforge.io/ attached to a suitable radio receiver.