Beginning in the early days of broadcasting, radio listeners developed the practice of writing to stations that they heard over long distances. They described the programming they heard, and asked the station to ‘verify’ in writing that it was indeed their station that was heard. Stations soon began responding to these ‘reception reports’ with their own distinctive ‘verification cards.’ These cards came to be known as ‘QSLs,’ the letters ‘Q-S-L’ being the international morse code symbol for ‘I acknowledge receipt.’
Most stations use specially designed QSL cards that are unique to them. These cards often convey a sense of the country’s history or culture, details about the station, the station emblem, etc. Usually they also contain details of the listener’s reception - date, time and frequency. Some stations, particularly the smaller ones, use letters instead of cards, often issued on decorative stationery.
Collecting QSLs became an important element in the hobby of long distance (‘DX’) radio listening, and remains so today. DX listening is only tangentially related to amateur radio, where radio operators talk with each other over their own transmitters (and also exchange QSLs of their contacts). The listening DXer does not talk over the air, but gets his or her pleasure in hearing new stations, writing to them and obtaining their QSL.
Library of American Broadcasting collection.