ok so ive been listening on 40m a lot lately and people throw around all these abbreviations and im just completely lost half the time. like QSO, QRM, QSB, QRN... i get that theyre some kind of shorthand but where did all this come from and is there like a master list somewhere? also heard someone say QRT and then the station just went silent, is that like signing off or something? sorry if this is a dumb question im only about 3 months into my technician license and still figuring everything out

Not a dumb question at all, Q codes go back to like the early 1900s telegraphs era, they were basically a way to communicate across language barriers because you could send a short code and someone in another country would know exactly what you meant even if they didnt speak english. QRT yeah that means stopping transmission or shutting down, so if somone says QRT theyre done for the night basically. QSO is just a contact or a conversation between two stations. QRM is man-made interference like someone elses signal bleeding in, QRN is natural static and noise like from thunderstorms. QSB is when your signal is fading in and out. ARRL has a pretty solid list on their website, just search ARRL Q codes and it should come right up. Youll pick em up fast once you start hearing them in context regularly, honestly after a few weeks of listening it just clicks.

yeah and there's a ton more that you'll run into. QTH is your location, QSL means confirming a contact which is also why those confirmation cards are called QSL cards. one that confused me for the longest time was QRP which just means low power operation, like 5 watts or less. people who run QRP rigs are super into the challenge of making contacts with minimal power. oh and QRZ is when someone is asking whos calling, so if you hear someone say QRZ? theyre asking who just called them. its a lot to take in at first but honestly most of the common ones you'll just memorize from hearing them over and over