Merchant-radio incompatibility during the Falklands War

During the 1982 Falklands War, the Royal Navy delivered messages to some merchant ships by helicopter, dropping boards with instructions written in chalk. Radio silence alone did not explain the problem: even the close-range sets used for convoy communication could fail to communicate with one another. Walkie-talkies were considered as a remedy. The sets obtainable quickly enough and in sufficient numbers were judged unsuitable. Civilian shipping could therefore sight a fleet yet lack the means to transmit a useful report.