June 30, 2008

Happy Birthday S O S

The London Times has the story:
SOS: the signal that has saved thousands turns 100
�Send SOS,� one of the Titanic�s radio operators supposedly said to another after the famous ship struck that infamous iceberg. �It�s the new call and besides this may be your last chance to send it.�

That �new call� is 100 years old today, and people around the world who owe their lives to that piece of Morse code may reflect this morning on its importance.

In the past century, �SOS� has become a firm part of popular culture used in everything from DIY programme titles to Abba hits. But it began life in a far more serious setting after being adopted by the international community on July 1, 1908, as the globally recognised distress signal for ships at sea.

At that time voices could not yet be carried across the airwaves and sailors needed a standard means of saying, in Morse code, that they were in trouble.

Until then, the most commonly used distress call was the �CQD� signal, which was open to misinterpretation. After much deliberation, SOS was chosen to replace it because the signal � three dots, three dashes and three more dots � is such a clear message to send in Morse code.
CQD is _._. --.- -.. SOS is ... --- ... Considering that a foundering ship may have electrical problems and the antennas may have become damaged or suffer reduced output and considering that many ships founder in storms with a lot of lightning and Continuous Wave Transmission (the type used then) was very susceptible to this kind of interference, it's a wonder that CQD was ever agreed on in the first place... There was a bit of a precedent in that importent messages were preceded by CQ CQ CQ so it did serve as a sort of "Attention all stations". Posted by DaveH at June 30, 2008 8:53 PM