Oh I actually know very little about radio on a technical side besides knowing the physics of it. Still, it is a topic I want to learn more about as the use of radio is very important as a tool of political expression. Clandestine radio has a very deep history and I might add some of it later here
These links take you to other websites, enter at your own risk.

QSL cards are like, cards that amateur radio operators can share as collectibles for when they manage to stabilish a connection. Kinda like a "Hey, I got you transmission. Here is this card". This, too, is yuri et cetera et cetera.

Some people like collecting those and they get some nice collections, and it is pretty cool to see the huge variety of amateur operators and creativity that people put into those

Wikipedia page on QSL cards This also has some nice links to QSL card related stuff (in the external links section), which I could link here, but its already there anyway

So, I am not an actuall radio operator, I do not have the training nor the equipment to do so (But its actually not THAT expensive, and I am in the process of learning). BUT, I will leave here my completely unoficial, and mostly meaningless QSL card, as more of a symbol of uh hey I saw your website. Save it, print it, hang it in your wall, car, whatever, go nuts, show nuts, be free e t c