Radio Prague’s 2021 QSL Cards
by Thomas from The SWLing Post on (#5CZN8)
(Source: Radio Prague International via David Iurescia) The three letters - QSL - constitute one of the codes originally developed in the days of the telegraph. All codes consisted of three letters beginning with Q". Later some of these Q" codes were adopted by radio-telegraphists and radio listeners. QSL means contact confirmed" or reception confirmed". [...]