QSL is an abbreviation that is used in amateur radio and CB radio communications to confirm a contact between two stations. It is a confirmation of communication between two stations, and it is typically sent in the form of a card. The card includes details of the contact, such as the date, time, frequency, and the signal report (a measure of the strength and quality of the received signal).

QSL cards can be sent via the mail, or electronically through various digital QSL systems.

The purpose of QSL cards is to serve as a record of the contact for both stations, and it is also a way for hams and CB operators to collect and exchange information about different stations and locations. Many hams and CB operators enjoy collecting QSL cards from other stations as a hobby and it’s also used as a way to confirm the authenticity of a contact for awards and contests.

QSL cards are usually exchanged via the mail or electronically, but sometimes, in-person QSL card exchanges are organized at hamfests (ham radio conventions) or CB events.

It’s also worth noting that QSL cards are not only used for casual contacts but also for contacts made during contests and other operating events, and it’s a way for operators to keep track of their progress and achievements.