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CQD in Morse code
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CQD (transmitted in Morse code as ▄▄▄ ▄ ▄▄▄ ▄  ▄▄▄ ▄▄▄ ▄ ▄▄▄  ▄▄▄ ▄ ▄ ) is one of the first distress signals adopted for radio use. On 7 January 1904 the Marconi International Marine Communication Company issued "Circular 57", which specified that, for the company's installations, beginning 1 February 1904 "the call to be given by ships in distress or in any way requiring assistance shall be 'C Q D'".[1]

Background

[edit]

Landline and submarine telegraphers' telegraphs had adopted the convention of using the station code "CQ" to all stations along a telegraph line. As the first wireless operators were taken from the already trained landline telegraphers, the current practices carried forward and CQ had then been adopted in maritime radiotelegraphy as a "general call" to any ship or land station.[2]

The Marconi company added a "D" ("distress") to CQ in order to create a distress call. Thus, "CQD" was understood by wireless operators to mean All stations: Distress.[a] Although used worldwide by Marconi operators, CQD was never adopted as an international standard, since it can easily be mistaken for a mere general call "CQ" when reception is poor.[4]

Replacement

[edit]

At the first International Radiotelegraphic Convention, held in Berlin in 1906, Germany's Notzeichen distress signal of three-dots three-dashes three-dots ( ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ ) was adopted as the international Morse code distress signal.[5]

This signal soon became known as SOS because it has the same dash-dot sequence as the letters with the gaps between them removed, and in fact is properly written SOS, with an overbar, to distinguish it from the three individual letters[citation needed]. In contrast, CQD is transmitted as three distinct letters with a short gap between each, like regular text. SOS is also easier to hear as it is nine symbols long, while no other character or sign is longer than six symbols. Germany had first adopted SOS in regulations effective 1 April 1905.[6][7]

History of wireless distress rescues

[edit]

From 1899 to 1908, nine documented rescues were made by the use of wireless. The earliest of these was a distress call from the East Goodwin lightship. However, for the earliest of these, there was no standardized distress signal. The first US ship to send a wireless distress call in 1905 simply sent HELP (in both International Morse and American Morse code).[3]: 218 

On 7 December 1903, Ludwig Arnson was a wireless operator aboard the liner SS Kroonland when the ship lost a propeller off the Irish coast. His call of CQD brought aid from a British cruiser. In 1944 Arnson received the Marconi Memorial Medal of Achievement of the Veteran Wireless Operators Association, in recognition of his sending the first CQD wireless distress signal from an American vessel.[8] By February 1904, the Marconi Wireless Company required all its operators to use CQD for a ship in distress or for requiring URGENT assistance.[1] In the early morning of 23 January 1909, whilst sailing into New York from Liverpool, RMS Republic collided with the Italian liner SS Florida in fog off the Massachusetts island of Nantucket. Radio Operator Jack Binns sent the CQD distress signal by wireless transmission.[9][10]

On 15 April 1912, RMS Titanic radio operator Jack Phillips initially sent "CQD", which was still commonly used by British ships. Harold Bride, the junior radio operator, suggested using SOS, saying half-jokingly that it might be his last chance to use the new code. Phillips thereafter began to alternate between the two.[3]: 1911  Although Bride survived, Phillips perished in the sinking.[11]

See also

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Footnotes

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References

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Bibliography

[edit]
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CQD

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CQD is a historical in radiotelegraphy, adopted by the Marconi International Marine Communication Company on , 1904, as a call for ships in peril, combining the general call "CQ" with "D" to indicate distress, effectively meaning "All stations, distress." Introduced amid the early expansion of communication at sea, CQD served as one of the first standardized radio signals for emergencies, filling a gap in international maritime protocols before a global standard emerged. The signal was transmitted in as –·–· ––·– –·· and was primarily used by Marconi-equipped vessels, becoming a procedural rather than a strict , despite popular misconceptions linking it to phrases like "Come Quick, Danger." CQD gained worldwide notoriety during the sinking of the RMS Titanic on April 15, 1912, when Marconi operator Jack Phillips initially broadcast it multiple times following the ship's collision with an , alerting nearby vessels like the to the disaster. Phillips later interspersed CQD with the newer signal at the urging of his colleague , marking one of the first uses of the emerging international code. Although effective, CQD was gradually supplanted by , which was adopted at the 1906 International Radiotelegraphic Convention in and became mandatory for international use starting July 1, 1908, due to its simpler transmission (··· ––– ···) and unambiguous recognition. By the , CQD had largely faded from use, persisting only in British Marconi operations until fully replaced, symbolizing the evolution from company-specific protocols to unified global maritime safety standards.

Development and Adoption

Origins of the Signal

The distress signal CQD emerged from established practices in 19th-century , where the "CQ" served as a general call to all stations, signaling " all" or a notification for urgent messages to postal telegraph offices. This originated in the United Kingdom's telegraph systems, including those operated by the British Post Office after it nationalized private lines in , where operators used it to alert multiple recipients on shared lines without specifying a single addressee. Early precedents for such abbreviations trace back to the mid-1800s, as telegraph networks expanded across and , standardizing to streamline communication amid increasing message volumes. As wireless telegraphy developed in the late 1890s and early 1900s, "CQ" was adapted for maritime radio use, retaining its role as a broadcast call to all ships or stations within range, meaning "all stations" or "calling all." This adaptation addressed the growing reliance on shipboard wireless amid expanding transatlantic shipping, but lacked a dedicated emergency indicator, leading operators to improvise during crises using visual signals or ad hoc codes. The need for a clear, urgent distress protocol became evident at the 1903 Preliminary Conference on Wireless Telegraphy in Berlin, where international delegates discussed standardizing radio procedures, including emergency calls, though no consensus was reached. To fill this gap, Marconi operators proposed CQD in 1904 by appending "D" to "CQ" to explicitly denote "distress," creating a specific signal for emergencies that leveraged the familiarity of the base code while emphasizing urgency in contexts. This derivation ensured immediate recognition among trained telegraphers, who understood "CQ" as a broad alert, with the added "D" prioritizing life-saving responses over routine traffic. The proposal reflected the rapid evolution of radio from novelty to essential maritime tool, driven by incidents highlighting the limitations of unregulated signaling.

Introduction by Marconi Company

The issued Circular No. 57 on January 7, 1904, formally establishing "CQD" as the standard for its -equipped ships, effective from February 1, 1904. The circular stipulated that "CQD" must be used exclusively in situations of extreme peril to the vessel or human life, issued only on the captain's direct order, and that it superseded all other transmissions to ensure immediate attention. This measure addressed the prior ambiguity in protocols, where the general call "CQ"—derived from practices—lacked a dedicated variant. Guglielmo Marconi, as the founder and driving force behind the company, played a pivotal role in advocating for such standardized procedures to improve the reliability of maritime wireless communication amid growing adoption of the technology. His vision emphasized the integration of clear, urgent signaling to mitigate risks at sea, reflecting the company's broader push for proprietary advancements in radiotelegraphy. Despite these efforts, the mandate applied solely to ships fitted with Marconi apparatus, restricting "CQD" to the company's network and contributing to non-universal adoption across the global fleet. Competing wireless providers, such as German firms using variants like "SOE," operated under different codes, which fostered challenges during cross-system interactions on international voyages. To support implementation, Marconi's early operator training programs and guidelines underscored "CQD"'s absolute precedence, instructing personnel to halt all routine messaging upon detection of the signal, establish contact without delay, and retransmit if necessary for distressed vessels. Violations, including unauthorized use, were grounds for immediate dismissal, reinforcing disciplined adherence to the protocol.

Usage and Technical Details

Morse Code and Transmission

The distress signal CQD was encoded in International Morse code as the sequence for the letters C (− · − ·), Q (− − · −), and D (− · ·), forming a total of nine symbols transmitted with standard pauses between the letters. Early radiotelegraph equipment used for transmitting CQD employed damped spark transmitters, which generated short bursts of radio waves through an electric spark across a gap, producing a characteristic "damped wave" signal suitable for Morse code modulation. These systems operated on varying wavelengths in the early years, typically longer than 600 meters, with 500 kHz (600 meters) becoming the international standard frequency for maritime distress calls following the 1906 Berlin Radiotelegraphic Convention and effective from 1908. Wireless operators followed procedures that involved rapidly keying the repeatedly on a manual to alert nearby stations, often prefixing it with the vessel's unique callsign—such as MGY for the RMS Titanic—to identify the source. Transmissions were powered by high-output generators, with main sets delivering up to 5 kW to achieve reliable signal strength over maritime distances. Transmission faced significant challenges, including interference from such as static from and solar activity, which could obscure signals in early spark-based systems. Effective range was limited to approximately 50-200 miles during daylight hours due to propagation, though it could extend to several hundred miles at night via ionospheric reflection, necessitating skilled operators capable of high-speed Morse transmission at 20 words per minute or more to cut through noise.

Early Maritime Applications

An early use of the CQD distress signal, predating its formal adoption, occurred on December 7, 1903, aboard the Red Star Line SS Kroonland, when wireless operator Ludwig Arnson transmitted it after the vessel lost a in a severe gale off the Irish coast. Arnson communicated with the Brow Head station approximately 78 miles west of Fastnet Rock, demonstrating wireless aid in maritime emergencies. Following this incident, the Marconi International Marine Communication Company formally adopted CQD as its standard distress signal through Circular 57, issued on , 1904, and effective from , with operators instructed to use it only on the captain's orders or to relay it from other vessels. From 1904 onward, CQD was integrated into the Marconi wireless rooms—dedicated onboard facilities equipped with spark-gap transmitters and coherers—on an increasing number of and ships, where operators received specific to monitor for the signal continuously and accord it absolute priority over all commercial, passenger, or governmental traffic. This ensured that distress calls interrupted routine operations, allowing dedicated focus on rescue coordination. Under the established protocol, transmission of CQD by any equipped vessel required all nearby Marconi stations to immediately cease other transmissions, acknowledge receipt, and respond with their position and offers of assistance, thereby facilitating rapid location and aid without interference. Larger ships maintained two operators for round-the-clock vigilance, while smaller vessels followed a of calling "CQ" (general call to all stations) and listening for set intervals to detect potential distress signals. By 1908, over 100 ships across major lines such as Cunard, White Star, and Hamburg-Amerika were fitted with Marconi systems, enabling widespread but network-restricted use; however, incompatibility with rival technologies, like those from the German Slaby-Arco or American Telefunken firms, often hindered responses from non-Marconi vessels, underscoring early limitations in .

Key Historical Events

Pre-Titanic Incidents

Between 1899 and 1908, facilitated nine documented rescues at sea, demonstrating the emerging reliability of Marconi's system in maritime emergencies. One early example occurred on December 1903, when the SS Kroonland, a ocean liner en route from to New York, experienced a steering gear breakdown approximately 30 miles from Fastnet Rock off . The ship's Marconi operator used the wireless apparatus to transmit messages to the Crookhaven shore station in , alerting shipowners and reassuring passengers while coordinating initial assistance, though specific distress signals like CQD were not yet standardized. A pivotal pre-Titanic incident highlighting CQD's took place on , 1909, when the White Star Line's RMS Republic collided with the Italian liner SS Florida in dense fog off Island, . Marconi operator Jack Binns immediately sent the CQD at 6:40 a.m., which was received by the Siasconset station on and relayed to nearby vessels. This marked the first all- rescue operation in history, with seven ships—including the RMS Baltic—responding to coordinate the evacuation of over 1,500 passengers and crew from both vessels via lifeboats, despite six fatalities from the initial impact. Binns's actions saved hundreds of lives and underscored telegraphy's potential for large-scale maritime coordination, prompting the U.S. Wireless Ship Act of 1910, which mandated radio equipment on ocean steamers carrying 50 or more persons and traveling more than 200 miles from shore. Later that year, on June 10, 1909, the Cunard liner SS Slavonia ran aground on a two miles southwest of Flores Island in the , becoming a total wreck as water flooded the vessel. Wireless operator S. Coles transmitted the signal, which was picked up 180 miles away by the steamers Prinzess Irene and Batavia, enabling swift rescue efforts. The distress call was relayed through stations, resulting in the safe evacuation of all 410 passengers—110 cabin passengers transferred to the Prinzess Irene and 300 to the Batavia—along with the 150 crew members who reached shore at Velas on Flores Island, with only minor injuries reported.

The RMS Titanic Disaster

The RMS Titanic collided with an iceberg at 11:40 p.m. on , 1912, in the North . Approximately 35 minutes later, at 12:15 a.m. on April 15, senior wireless operator Jack Phillips began transmitting the CQD from the ship's Marconi room, alerting nearby vessels to the emergency and providing the Titanic's position at 41°46′N 50°14′W. These initial calls were received by several ships, including the , which was approximately 58 miles away and immediately altered course to assist under Captain Arthur Rostron's orders. As the situation worsened, Phillips continued sending CQD signals but later incorporated the newly adopted distress call in accordance with British regulations, alternating between the two to maximize reach; assistant operator , who had been roused from sleep, suggested the switch and later relieved Phillips around 2:00 a.m. as flooded the room. The operators relayed urgent pleas for help, such as "Come at once. We have struck a berg," directly to the Carpathia, coordinating the rescue amid interference from other ships' transmissions. Over 300 messages were transmitted in total during the crisis, enabling the Carpathia to arrive at the scene by 4:00 a.m., where it rescued 705 survivors from the Titanic's lifeboats; Phillips perished in the sinking, while survived after briefly assisting with lifeboat launches. The subsequent inquiry praised the operators' heroism, noting their refusal to abandon their posts even as seawater reached the upper deck, which exemplified the critical role of continuous communication in maritime safety. This led directly to the , which mandated 24-hour monitoring on large passenger ships to prevent similar communication lapses in future emergencies.

Replacement by SOS

Adoption of the International Standard

The push toward a unified international distress signal culminated in the International Radiotelegraph Convention held in , where delegates from 27 maritime nations agreed to adopt (··· ––– ···) as the global standard, replacing disparate signals like CQD. Signed on November 3, , the convention mandated its use on all ships equipped with , irrespective of the manufacturer, to ensure interoperability during emergencies at sea. This agreement aimed to standardize communications for , prioritizing signals that could be transmitted and received clearly across nationalities and types. Germany had pioneered SOS domestically through its national radio regulations effective April 1, 1905, selecting it as the "Notzeichen" () for its straightforward sequence of nine clear symbols without inter-letter pauses, which formed a distinct easier to recognize amid interference or operator . Unlike CQD, an prone to misinterpretation—such as being read as "Come Quick, Danger" or confused with procedural calls like "CQ" (all stations)—SOS was chosen for its non-abbreviated simplicity, avoiding linguistic ambiguities and enhancing transmission reliability. The convention built on this German proposal, formalizing SOS after discussions that favored its ease of over alternatives like the earlier German "SOE." The convention's provisions required wireless stations to interrupt all other traffic upon hearing SOS, responding immediately to aid the distressed vessel, with the signal repeatable at brief intervals for emphasis. Effective July 1, 1908, these rules marked a pivotal shift toward regulated radiotelegraphy, mandating SOS on international voyages to prevent the chaos of multiple competing signals. By establishing this uniform protocol, the 27 signatory nations— including major powers like the , , , , and —laid the groundwork for coordinated maritime rescue efforts.

Transition Period and Coexistence

Following the adoption of SOS as the international distress signal effective July 1, 1908, a transitional period ensued where both CQD and were employed by maritime radio operators, particularly among British Marconi personnel who retained a preference for the older CQD due to its established familiarity. This dual usage persisted until regulatory enforcement in 1912, as guidelines allowed operators to continue CQD practices despite the international standard. A notable example occurred aboard the RMS Titanic on April 14-15, 1912, where wireless operators Jack Phillips and interchangeably transmitted both signals during the ship's distress calls, beginning with CQD before incorporating at Bride's suggestion as an additional "new call" to maximize reach. The International Radiotelegraph Convention held in from June 4 to July 5, 1912—convened shortly after the Titanic disaster—reaffirmed SOS as the exclusive international distress signal in its annexed Service Regulations, emphasizing its procedural simplicity for urgent transmissions while standardizing wavelengths and operational protocols to reduce confusion. However, practical implementation varied; in the United States, CQD continued in limited use until the took full effect on December 13, 1912, explicitly mandating SOS ("...---...") as the sole distress call for licensed stations and requiring ships to maintain continuous radio watches for it. British operators, bound by Marconi traditions, exhibited slower adoption, with CQD lingering into the early years of despite the convention's directives. Challenges during this coexistence period arose from entrenched operator habits and inconsistencies in equipment calibration, which sometimes resulted in mixed or unclear distress transmissions that complicated rescue coordination. The Titanic incident highlighted these issues, as varying signal interpretations among nearby vessels delayed responses. The post-Titanic inquiries accelerated the shift to SOS exclusivity. The U.S. Senate Commerce Committee inquiry, concluding in May 1912, directly influenced the Radio Act of 1912 by recommending standardized distress procedures, thereby designating SOS as the mandatory U.S. signal and phasing out CQD as a legacy code. Similarly, the British Wreck Commissioner's inquiry, which reported in July 1912, urged enhanced wireless regulations and an international conference on telegraphy—implicitly supporting the ongoing London convention—while advocating for 24-hour operations to ensure reliable SOS reception, effectively relegating CQD to obsolescence by the war's onset in 1914. By World War I, SOS had achieved universal maritime compliance, marking the complete end of the transition era.

Legacy and Impact

Influence on Distress Signaling

The use of CQD as a distress signal during maritime emergencies, particularly exemplified by its transmission from the RMS Titanic in 1912, served as a catalyst for international regulations enhancing wireless communication reliability. In response, the United States enacted the , which mandated federal licensing for radio operators and required large passenger ships to maintain a continuous 24-hour radio watch for distress signals, directly addressing the intermittent monitoring that had previously hindered rescues. Internationally, this urgency contributed to the International Convention for the Safety of Life at Sea (SOLAS), which established Chapter IV on radiotelegraphy, requiring passenger ships to be fitted with installations capable of communicating over at least 100 nautical miles by day and mandating continuous 24-hour radio watches on large passenger ships to ensure prompt distress responses. CQD's emphasis on rapid, prioritized wireless alerts laid foundational principles for the evolution toward modern automated systems, culminating in the Global Maritime Distress and Safety System (GMDSS) implemented in 1999 under the (IMO). The GMDSS replaced Morse code-based signals like CQD and with digital technologies, including Emergency Position Indicating Radio Beacons (EPIRBs) for automatic location transmission and satellite communications via systems such as , enabling global coverage without reliance on ship-to-ship Morse transmissions. This shift, informed by the proven life-saving potential of early radio distress protocols, has facilitated rescues in remote areas where traditional methods would fail, integrating voice, data, and satellite relays for comprehensive safety. Beyond maritime applications, CQD pioneered the concept of dedicated, high-priority emergency signaling in radio communications, influencing protocols in and terrestrial systems. In , the voice distress call ""—adopted internationally in 1927 as the equivalent of —built on the maritime tradition of unambiguous alerts established by CQD, ensuring immediate channel clearance and coordinated responses during flight emergencies. Similarly, land-based emergency services adopted priority signaling hierarchies inspired by these wireless precedents, emphasizing rapid operator intervention and resource allocation in public safety radio networks. The technological legacy of CQD extends from rudimentary spark-gap transmitters to contemporary digital infrastructures, demonstrating radio's transformative role in emergency response and indirectly contributing to the of thousands through subsequent advancements. By validating technology's efficacy in real-time distress coordination during the early , CQD accelerated the integration of radio into global frameworks, evolving into resilient systems that mitigate and environmental challenges.

Cultural Significance

CQD has become an iconic element in the cultural lore surrounding the RMS Titanic, symbolizing the era's nascent wireless technology and human efforts to avert disaster. In James Cameron's 1997 film Titanic, the character of senior wireless operator Jack Phillips is shown frantically transmitting the CQD signal from the ship's radio room amid the chaos of the sinking, portraying it as a desperate plea that underscores themes of innovation and tragedy. This depiction draws from historical accounts and has cemented CQD's image in popular media as a hallmark of early 20th-century maritime heroism. Similarly, seminal such as Walter Lord's 1955 book A Night to Remember vividly recounts the transmission of CQD during the disaster, emphasizing its role in coordinating rescue efforts and influencing subsequent adaptations, including a 1958 film version that further popularized the signal's narrative significance. The British and American inquiries into the Titanic sinking also highlighted CQD transmissions in their reports, framing the code as a pioneering tool of communication that saved lives despite its limitations. A persistent cultural misconception surrounds CQD's origins, often misattributed as an acronym for "Come Quick, Danger" or similar phrases like "Come Quickly Down," which has permeated Titanic-related stories and folklore despite lacking official basis. In reality, CQD evolved from the Marconi Company's "CQ" general call sign, appended with "D" for distress, as established in early wireless protocols around 1904. This myth, debunked in historical analyses but enduring in public memory, reflects broader romanticization of Morse code signals in literature and media, where CQD is sometimes conflated with the later SOS to evoke urgency and peril. CQD is honored in maritime memorials and educational contexts as the first standardized wireless distress code, underscoring its foundational role in radio history. Exhibits at the in the UK feature reconstructions of early ship radio rooms, including Marconi equipment used for CQD transmissions, illustrating its contribution to safety advancements post-Titanic. The of Ireland's Radio Room display commemorates CQD's use during the disaster, highlighting the transition to SOS and the heroism of operators like Phillips and Bride. In educational programs, particularly within amateur radio communities, CQD is taught as a key milestone in distress signaling evolution, with organizations like the incorporating it into curricula on historical communication protocols. Echoes of CQD persist in modern media and commemorative events, reinforcing its symbolic legacy. During the 2012 Titanic centennial, amateur radio enthusiasts reenacted the original CQD distress calls from the sinking site aboard the MV Azamara Journey, linking the signal via satellite to historical sites like Cape Race, Newfoundland, to educate participants on early wireless technology. Such simulations are integrated into maritime and radio training exercises, where CQD serves as a case study for emergency protocols, emphasizing the importance of clear signaling in crisis response.

References

  1. https://www.wired.com/2008/01/dayintech-0107/
  2. https://navalmarinearchive.com/research/docs/sos.html
  3. https://www.sciencemuseum.org.uk/objects-and-stories/titanic-marconi-and-wireless-telegraph
  4. https://www.ac6v.com/73.php
  5. https://ethw.org/Telegraph
  6. https://www.eham.net/article/10338
  7. https://www.saturdayeveningpost.com/2023/02/in-a-word-sending-out-an-sos/
  8. https://www.mentalfloss.com/article/91565/international-distress-signal-predates-sos
  9. https://earlyradiohistory.us/1913dist.htm
  10. https://www.pbs.org/wgbh/americanexperience/features/rescue-wireless-signals/
  11. https://www.itu.int/dms_pubrec/itu-r/rec/m/r-rec-m.1677-1-200910-i!!pdf-e.pdf
  12. http://dougkerr.net/Pumpkin/articles/Titanic_wireless.pdf
  13. https://www.titanicinquiry.org/BOTInq/BOTInq26Marconi01.php
  14. https://media.defense.gov/2021/Sep/30/2002864733/-1/-1/0/HERSEY_RADIO-COMMS-HISTORY2012.PDF
  15. https://www.antiquewireless.org/wp-content/uploads/Vol.-25.pdf
  16. https://www.nytimes.com/1903/12/09/archives/the-kroonland-disabled-red-star-liner-first-to-use-wireless.html
  17. https://www.nytimes.com/1958/04/13/archives/ludwig-arnson.html
  18. https://www.nytimes.com/1909/02/14/archives/the-advance-of-wireless.html
  19. https://earlyradiohistory.us/1908uwa.htm
  20. https://www.worldradiohistory.com/BOOKSHELF-ARH/Technology/Technology-Early-Radio/Wireless-at-Sea-Hancock-1950.pdf
  21. https://its.ntia.gov/this-month-in-its-history/january-1909
  22. https://its.ntia.gov/this-month-in-its-history/june-1910
  23. https://www.nytimes.com/1909/06/13/archives/wireless-brought-help-to-slavonia-cunarder-now-total-wreck-on.html
  24. https://www.nationalgeographic.com/history/article/why-titanic-first-call-help-not-sos-signal
  25. https://www.titanicinquiry.org/USInq/USReport/AmInqRepSmith01.php
  26. https://www.smithsonianmag.com/history/titanic-sank-this-morning-102770115/
  27. https://earlyradiohistory.us/1906conv.htm
  28. https://www.itu.int/itunews/manager/display.asp?lang=en&year=2006&issue=06&ipage=pioneers&ext=html
  29. https://www.imo.org/en/OurWork/Safety/Pages/RadiaCommunicationsSearchRescue-Default.aspx
  30. https://www.itu.int/en/history/Pages/RadioConferences.aspx
  31. https://earlyradiohistory.us/1912act.htm
  32. https://www.titanicinquiry.org/BOTInq/BOTReport/botRepRec.php
  33. https://www.visitthecapitol.gov/artifact/s-6412-act-regulate-radio-communication-radio-act-1912-may-20-1912
  34. https://www.encyclopedia-titanica.org/titanic-impact-on-maritime-law.html
  35. https://www.nationalarchives.gov.uk/education/resources/the-convention-for-the-safety-of-life-at-sea-solas/
  36. https://www.imo.org/en/OurWork/Safety/Pages/Introduction-history.aspx
  37. https://science.howstuffworks.com/transport/flight/modern/mayday.htm
  38. http://www.paullee.com/titanic/jc1997goofs.php
  39. https://www.encyclopedia-titanica.org/sos-myth.html
  40. https://publications.gc.ca/collections/collection_2014/mpo-dfo/T31-107-1998-eng.pdf
  41. https://www.mariner.ie/Exhibition/radio-room/
  42. http://www.arrl.org/ham-radio-history
  43. https://www.arrl.org/news/inspiration-and-perspiration-rms-titanic-distress-signals-heard-again
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