Editing Spark-gap transmitter (section)

===The "spark" era===
The first application of radio was on ships, to keep in touch with shore, and send out a distress call if the ship were sinking.<ref name="White3">{{cite web
| last= White
| first= Thomas H.
| title= Section 12: Radio at Sea (1891-1922)
| work= United States Early Radio History
| publisher= T. H. White's personal website
| date= 2003
| url= https://earlyradiohistory.us/sec005.htm
| access-date= 2 October 2018}}</ref> The Marconi Company built a string of shore stations and in 1904 established the first Morse code distress call, the letters ''CQD'', used until the Second International Radiotelegraphic Convention in 1906 at which ''[[SOS]]'' was agreed on. The first significant marine rescue due to radiotelegraphy was the 23 January 1909 sinking of the luxury liner [[RMS Republic (1903)|RMS ''Republic'']], in which 1500 people were saved.

{| style="background:#e0e0e0;" align="right" border="1" cellpadding="5" cellspacing="0"
! colspan="4" style="background:#c0c0c0; text-align:center;" |Radio frequencies used by spark transmitters during the wireless telegraphy era<ref name="Moorcroft">{{cite book |last1= Moorcroft |first1= John Harold |last2= Pinto |first2= A. |last3= Curry |first3= Walter Andrew |title= Principles of Radio Communication |publisher= John Wiley and Sons |date= 1921 |pages= [https://archive.org/details/principlesradio03currgoog/page/n373 357] |url= https://archive.org/details/principlesradio03currgoog }}</ref>
|-
! style="background:#d0d0d0; text-align:center;" | Uses
! style="background:#d0d0d0; text-align:center;" border="1" | Frequency<br/>(kilohertz)
! style="background:#d0d0d0; text-align:center;" border="1" | Wavelength<br/>(meters)
! style="background:#d0d0d0; text-align:center;" | Typical power<br/> range (kW)
|-
| valign="top" | Amateur || > 1500 || < 200 || 0.25 - 0.5
|-
| Ships || 500, 660, 1000 || 600, 450, 300 || 1 - 10
|-
| Navy || 187.5 - 500 || 1600 - 600 || 5 - 20
|-
| Moderate size land stations || 187.5 - 333 || 1600 - 900 || 5 - 20
|-
| Transoceanic stations || 15 - 187.5 || 20,000 - 1600 || 20 - 500
|}

Spark transmitters and the [[crystal radio|crystal receivers]] used to receive them were simple enough that they were widely built by hobbyists.<ref name="Hyder" /> During the first decades of the 20th century this exciting new high tech hobby attracted a growing community of "[[radio amateur]]s", many of them teenage boys, who used their homebuilt sets recreationally to contact distant amateurs and chat with them by Morse code, and relay messages.<ref name="CodellaSqueakBox">{{cite web
| last= Codella
| first= Christopher F.
| title= The Squeak Box
| work= Ham Radio History
| publisher= Codella's private website
| date= 2016
| url= http://w2pa.net/HRH/the-squeak-box/
| access-date= 22 May 2018}}</ref><ref name="White2">{{cite web
| last= White
| first= Thomas H.
| title= Section 12: Pioneering Amateurs (1900-1912)
| work= United States Early Radio History
| publisher= earlyradiohistory.us
| date= 2003
| url= https://earlyradiohistory.us/sec012.htm
| access-date= 26 June 2018}}</ref> Low-power amateur transmitters ("squeak boxes") were often built with "[[trembler coil|trembler]]" [[ignition coil]]s from early automobiles such as the [[Ford Model T]].<ref name="CodellaSqueakBox"/> In the US prior to 1912 there was no government regulation of radio, and a chaotic "wild west" atmosphere prevailed, with stations transmitting without regard to other stations on their frequency, and deliberately interfering with each other.<ref name="White2" /><ref name="Howeth2">{{cite book
| last1= Howeth
| first1= L. S.
| title= The History of Communications - Electronics in the U.S. Navy
| publisher= U.S. Navy
| date= 1963
| pages= 69, 117
| url= https://archive.org/stream/historyofcommuni00howe#page/116
}}</ref><ref name="CodellaFirstRegulation"/> The expanding numbers of non-syntonic broadband spark transmitters created uncontrolled congestion in the airwaves, interfering with commercial and military wireless stations.<ref name="CodellaFirstRegulation">{{cite web
| last= Codella
| first= Christopher F.
| title= The first regulations
| work= Ham Radio History
| publisher= Codella's private website
| date= 2016
| url= http://w2pa.net/HRH/the-first-regulations/
| access-date= 22 May 2018}}</ref>

The {{RMS|Titanic}} sinking 14 April 1912 increased public appreciation for the role of radio, but the loss of life brought attention to the disorganized state of the new radio industry,<ref name="SanFranciscoCall">{{cite news
  | title = To Check Wireless Anarchy
  | newspaper = San Francisco Call
  | location = San Francisco, California
  | pages = 22
  | language = 
  | publisher = Charles Shortridge
  | date = 7 July 1912
  | url = https://chroniclingamerica.loc.gov/lccn/sn85066387/1912-07-07/ed-1/seq-22/
  | access-date = 5 February 2024}}</ref> and prompted regulation which corrected some abuses.<ref name="White2"/> Although the ''Titanic'' radio operator's ''CQD'' distress calls summoned the {{RMS|Carpathia}} which rescued 705 survivors, the rescue operation was delayed four hours because the nearest ship, the [[SS Californian|SS ''Californian'']], only a few miles away, did not hear the ''Titanic''{{'}}s call as its radio operator had gone to bed. This was held responsible for most of the 1500 deaths.  Existing international regulations required all ships with more than 50 passengers to carry wireless equipment, but after the disaster subsequent regulations mandated ships have enough radio officers so that a round-the-clock radio watch could be kept.  US President Taft and the public heard reports of chaos on the air the night of the disaster, with amateur stations interfering with official naval messages and passing false information.<ref name="SanFranciscoCall" /><ref name="NewYorkHerald">{{cite news
  | title = President Moves to Stop Mob Rule of Wireless
  | newspaper = New York Herald
  | location = New York, NY
  | pages = 2
  | language = 
  | publisher = James Gordon Bennett, Jr.
  | date = 17 April 1912
  | url = https://fultonhistory.com/Newspaper%2014/New%20York%20NY%20Herald/New%20York%20NY%20Herald%201912/New%20York%20NY%20Herald%201912%20-%203562.pdf
  | access-date = 5 February 2024}}</ref>  In response Congress passed the 1912 Radio Act, in which licenses were required for all radio transmitters, maximum damping of transmitters was limited to a decrement of 0.2 to get old noisy non-syntonic transmitters off the air, and amateurs were mainly restricted to the unused frequencies above 1.5&nbsp;MHz and output power of 1 kilowatt.<ref name="RadioAct1912"/><ref name="CodellaFirstRegulation"/><ref name="Hyder" />

[[File:Quenched spark transmitter - Nauen Radio Station, Nauen Germany 1921.jpg|thumb|Telefunken 100&nbsp;kW transoceanic quenched spark transmitter at [[Nauen Transmitter Station]], [[Nauen]], Germany was the most powerful radio transmitter in the world when it was built in 1911]]

The largest spark transmitters were powerful transoceanic radiotelegraphy stations with input power of 100 - 300&nbsp;kW.<ref name="Pickworth">{{cite journal
| last1= Pickworth
| first1= George
| title= Marconi´s 200kW transatlantic transmitter
| journal= Electronics World
| volume= 102
| issue= 1718
| date= January 1994
| url= http://hjem.get2net.dk/helthansen/marconi_tx.htm
| archive-url = https://archive.today/20021020055257/http://hjem.get2net.dk/helthansen/marconi_tx.htm
| archive-date = 2002-10-20
| url-status = dead
| access-date= 22 March 2018}}</ref><ref name="Bucher1">{{cite book
| last1= Bucher
| first1= Elmer E.
| title= Practical Wireless Telegraphy
| publisher= Wireless Press, Inc.
| date= 1917
| location= New York
| pages= 288–307
| url= https://archive.org/stream/wirelesstele00buchrich#page/302/mode/2up
}}</ref> Beginning about 1910, industrial countries built global networks of these stations to exchange commercial and diplomatic [[telegram]] traffic with other countries and communicate with their overseas colonies.<ref name="Leggett4">{{cite journal
| last1= Leggett
| first1= Bernard John
| title= Wireless Telegraphy, with special reference to the quenched-spark system
| journal= Nature
| volume= 107
| issue= 2691
| date= 1921
| pages= 299–305
| url= https://books.google.com/books?id=b843AAAAMAAJ&pg=PA299
| doi= 10.1038/107390b0
| bibcode= 1921Natur.107..390.
| hdl= 2027/mdp.39015063598398
| s2cid= 4075587
| hdl-access= free
}}</ref><ref name="Lescarboura">{{cite book
| last1= Lescarboura
| first1= Austin C.
| title= Radio for Everybody
| publisher= Scientific American Publishing Co.
| date= 1922
| pages= [https://archive.org/details/RadioForEverybody/page/n279 259]–263
| url= https://archive.org/details/RadioForEverybody
}}</ref><ref name="Headrick">{{cite book
| last1= Headrick
| first1= Daniel R.
| title= The Tentacles of Progress: Technology Transfer in the Age of Imperialism, 1850-1940
| publisher= Oxford University Press
| date= 1988
| location= New York
| pages= 126–130
| url= https://books.google.com/books?id=0wjDxYlArQAC&pg=PA126
| isbn= 978-0198021780
}}</ref> During [[World War I]], radio became a strategic defensive technology, as it was realized a nation without long distance radiotelegraph stations could be isolated by an enemy cutting its [[submarine telegraph cable]]s.<ref name="Lescarboura" />   Most of these networks were built by the two giant wireless corporations of the age: the British [[Marconi Wireless Telegraph Co|Marconi Company]], which constructed the [[Imperial Wireless Chain]] to link the possessions of the [[British Empire]], and the German [[Telefunken]] Co. which was dominant outside the British Empire.<ref name="Leggett4"/> Marconi transmitters used the timed spark rotary discharger, while Telefunken transmitters used its quenched spark gap technology. [[punched paper tape|Paper tape machines]] were used to transmit Morse code text at high speed. To achieve a maximum range of around 3000 – 6000 miles, transoceanic stations transmitted mainly in the [[very low frequency]] (VLF) band, from 50&nbsp;kHz to as low as 15 – 20&nbsp;kHz. At these wavelengths even the largest antennas were [[electrically short]], a tiny fraction of a wavelength tall, and so had low [[radiation resistance]] (often below 1 ohm), so these transmitters required enormous wire [[umbrella antenna|umbrella]] and [[T-antenna|flattop]] antennas up to several miles long with large capacitive toploads, to achieve adequate efficiency. The antenna required a large [[loading coil]] at the base, 6 – 10 feet tall, to make it resonant with the transmitter.