Editing Loran-C (section)

===Loran-A===
{{Main|LORAN}}
The original LORAN was proposed in 1940 by [[Alfred Lee Loomis]] at a meeting of the U.S. Army's Microwave Committee. The [[United States Army Air Corps|Army Air Corps]] were interested in the concept for aircraft navigation, and after some discussion they returned a requirement for a system offering accuracy of about {{convert|1|mi|km}} at a range of {{convert|200|mi|km}}, and a maximum range as great as {{convert|500|mi|km}} for high-flying aircraft. The Microwave Committee, by this time organized into what would become the [[MIT Radiation Laboratory]], took up development as '''Project 3'''. During the initial meetings, a member of the UK liaison team, [[Edward George Bowen|Taffy Bowen]], mentioned that he was aware the British were also working on a similar concept, but had no information on its performance.{{sfn|Halford|Davidson|Waldschmitt|1948|p=19}}

The development team, led by Loomis, made rapid progress on the transmitter design and tested several systems during 1940 before settling on a 3&nbsp;MHz design. Extensive signal-strength measurements were made by mounting a conventional radio receiver in a [[station wagon]] and driving around the eastern states.<ref name=halford>Halford, Davidson and Waldschmitt, [https://www.jlab.org/ir/MITSeries/V4.PDF "History of LORAN"] {{Webarchive|url=https://web.archive.org/web/20160923030014/https://www.jlab.org/ir/MITSeries/V4.PDF |date=23 September 2016 }}, MIT Radiation Laboratory, pp. 19-23.</ref> However, the custom receiver design and its associated [[cathode-ray tube]] displays proved to be a bigger problem. In spite of several efforts to design around the problem, instability in the display prevented accurate measurements as the output shifted back and forth on the face of the oscilloscope.{{sfn|Blanchard|1991|pp=305–306}}

By this time the team had become much more familiar with the British [[Gee (navigation)|Gee]] system, and were aware of their related work on "strobes", a [[time base generator]] that produced well-positioned "pips" on the display that could be used for accurate measurement. This meant that inaccuracy of the positioning on the display had no effect: any inaccuracy in the position of the signal was also in the strobe, so the two remained aligned. The Project 3 team met with the Gee team in 1941, and immediately adopted this solution. This meeting also revealed that Project 3 and Gee called for almost identical systems, with similar performance, range and accuracy, but Gee had already completed basic development and was entering into initial production, making Project 3 superfluous.{{sfn|Halford|Davidson|Waldschmitt|1948|p=22}}

In response, the Project 3 team told the Army Air Force to adopt Gee, and instead, at the behest of the British team, realigned their efforts to provide long-range navigation on the oceans where Gee was not useful. This led to [[United States Navy]] interest, and a series of experiments quickly demonstrated that systems using the basic Gee concept, but operating at a lower frequency around 2&nbsp;MHz would offer reasonable accuracy on the order of a few miles over distances on the order of {{convert|1250|mi|km}}, at least at night when signals of this frequency range were able to skip off the [[ionosphere]].{{sfn|Halford|Davidson|Waldschmitt|1948|p=22}} Rapid development followed, and a system covering the western Atlantic was operational in 1943. Additional stations followed, first covering the European side of the Atlantic, and then a large expansion in the Pacific. By the end of the war, there were 72 operational LORAN stations and as many as 75,000 receivers.

In 1958 the operation of the LORAN system was handed over to the [[United States Coast Guard]], which renamed the system "Loran-A", the lower-case name being introduced at that time.{{sfn|Hefley|1972|p=xi}}