Atlantic to New York City or London. The equipment was owned by Marconi's Wireless. Telegraph Co. and operated by two of its employees, Jack Phillips and ...
history “PLEASE RUSH ALL POSSIBLE ASSISTANCE”
How the sinking of the Titanic sparked a century of radio reform
When the RMS Titanic scraped an iceberg on the night of 14 April 1912, its wireless operators began sending distress calls on one of the world’s most advanced radios: a 5-kilowatt rotary spark transmitter that on a clear night could send signals from the middle of the Atlantic to New York City or London. The equipment was owned by Marconi’s Wireless Telegraph Co. and operated by two of its employees, Jack Phillips and Harold Bride. What Phillips and Bride lacked, however, were international protocols for wireless communications at sea. Shipboard operators were still an unregulated novelty, and they reported to their companies, not to the ship captain. They sent business and personal messages alike using assorted spark transmitters over various wavelengths. The vast majority of ships had only one radio operator, who was obligated to serve only a 10-hour shift each day. Efforts to regulate wireless at sea drew challenges from governments and corporations— most notably Marconi’s own company. But after a series of maritime accidents in the early 20th century, the need to standardize procedures and systems for wireless maritime distress became increasingly apparent. The Titanic’s sinking accelerated a process that to this day continues to improve communications technology at sea. —Alexander B. Magoun
1 February 1904: Marconi’s company adopts “CQD” to signal maritime distress. “CQ” is a homophone of sécu, short for sécurité, used to designate important telegraph messages.
May 1897: Alexander Popov demonstrates shore-to-ship wireless telegraphy in the Gulf of Finland.
24 December 1898: Guglielmo Marconi demonstrates ship-toshore wireless contact near Dover, England.
11 March 1899: The Elbe runs aground in the English Channel. The East Goodwin Lightship sends the first wireless distress call.
1 April 1905: Germany adopts “SOS” as its distress signal.
10 April 1912: The RMS Titanic sets sail from Southampton, England. Radio equipment includes a synchronous rotary spark transmitter driven by a 5-kilowatt motor-generator that draws 100-volt DC from the ship’s lighting circuit and converts it to AC. The setup is powerful enough to send Morse code signals up to 700 kilometers by day and 3200 km by night. The transmitter generates radio waves by means of spark gaps: Electrodes mounted on a rotating metal disk driven by the motor-generator pass by two electrodes fixed to an outer cylinder; as the telegraph key is depressed, high-voltage sparks jump the gap between the fixed and rotating electrodes. Signals travel through a four-wire, 180-meter-long Marconi twin “T” type antenna, strung between the ship’s two 60-meter masts.
24 June 1910: U.S. President William Howard Taft signs a law requiring ships visiting U.S. ports to install wireless equipment.
14 April 1912: The Titanic strikes an iceberg at 11:40 p.m. Radio operator Jack Phillips begins transmitting “CQD MQY” (MQY were the Titanic’s call letters) 35 minutes later. At fellow operator Harold Bride’s suggestion, Phillips also begins sending “SOS MQY.” The Frankfurt is the first to answer the call, followed by the Olympic (Titanic’s sister ship), the Carpathia, the Baltic, and several others. But the ship closest to the Titanic, the Californian, does not respond; its radio operator had switched off his equipment for the night 10 minutes before the Titanic struck ice.
The Titanic’s Radio System This schematic shows a typical Marconi marine 5-kilowatt wireless transmitting set, of the type installed on the Titanic. Much of the transmitting equipment was kept in a separate cabin, known as the Silent Room, while the operators worked in the Marconi Room.
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15 April 1912: The Titanic sinks at 2:20 a.m. Of the 2200 or so people aboard, about 1500 die. The Carpathia arrives at 4:00 a.m. 16 April 1912: David Sarnoff, wireless station manager at Wanamaker’s department store in New York City (and future president of RCA), informs a supervisor that the Titanic has sunk and that the Carpathia is the only ship with survivors.
July–August 1912: On 5 July, the International Radiotelegraph Convention in London adopts the distress signal “SOS,” along with continuous staffing of ships’ wireless stations. Within several weeks, U.S. laws are similarly updated, with new provisions requiring radio stations and operators to be licensed.
1948: A United Nations convention adopts 2182 kilohertz as the new distress frequency.
1 November 1974: New rules require ships over 300 metric tons to carry satellitebased emergency radio beacons and search-and-rescue transponders.
1988: Emergency ship communications are carried by the Inmarsat network.
2004: Ships now must have two means of transmitting ship-toshore distress alerts: at 156.3 megahertz and at 406 MHz or 1.6 gigahertz.
For a complete list of references and sources, see http://spectrum.ieee.org/ titanicsources0412. Images: Clockwise from top: ITAR-TASS Photo Agency/ Alamy; mckibillo (3); Spaarnestad Photo/Redux; mckibillo; Library of Congress
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