Television in 1926: http://www.earlytelevision.org/yanczer_sanabria.html Wide and very interesting series of discourses on abbreviations and codes in use today. Historical background included for most http://www.ac6v.com/73.htm#cq The missing "Q" signals: http://www.zerobeat.net/drakelist/missingq.html (Thanks to K5FNI and N4ICK for sharing)