QSLs

QSLs, or QSL cards, are written confirmations exchanged by amateur radio operators to verify that a two-way contact occurred between stations. Traditionally these confirmations arrive as physical postcards mailed between operators, but today many confirmations are exchanged electronically. QSLs serve as a record of a contact and are often used to support awards and ratings.

A QSL card typically contains essential details of the contact, including the date and time in Coordinated Universal Time (UTC), the frequency or band, the operating mode (for example CW, SSB, or digital modes), the call signs of both stations, signal reports, and the location or operator names as provided by the sender. Some cards also include a QTH (location), operator details, or a serial contact number.

Delivery methods vary. Paper QSLs are commonly exchanged via mail directly between operators, or through QSL bureaus, which pool and forward confirmations to members to reduce postage costs. Direct mail between stations can incur postage and handling fees, while bureau routes may take longer. Electronic QSLs are also widely used through services that offer digital confirmations, sometimes sharing data with other logging systems.

Two major systems for electronic confirmations are the ARRL's Logbook of The World (LoTW) and the international eQSL service. LoTW uses cryptographic authentication and requires uploaded logs to match confirmations. eQSL provides a web-based interface and digital confirmations, often with optional certificate features.

QSLs are valued by collectors and are integral to many amateur radio activities and awards, including DXCC and state or country-based awards. They also reflect the historical culture of radio communication and the effort involved in confirming long-distance contacts.