In the 1940s, ATC centres could and did take advantage of the newly developed radar and improved radio communication brought about by the Second World War, but the system remained rudimentary.

在20世纪40年代，空中交通管制中心能够而且确实利用了第二次世界大战中新研制的雷达和改进的无线电通讯，但是这个系统还处于初级阶段。

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However, this purely visual system was useless in bad weather, and, by the 1930s, radio communication was coming into use for ATC.

然而，这种纯粹的视觉系统在恶劣天气下毫无用处，到了20世纪30年代，无线电通信开始用于空中交通管制。

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In 1969, the Radio Amateur Satellite Corporation (AMSAT) was created in order to foster ham radio enthusiasts' participation in space research and communication.

1969年，国际业余卫星组织（AMSAT）成立了，其目的是促进业余无线电爱好者参与并讨论太空研究。

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The North says it will stop using maritime shortwave radio frequencies with the South and cut off other means of emergency communication.

VOA: standard.2010.05.27

The site is home to transmitters for most of the city's television stations, as well as some radio stations, several mobile phone companies and police communication systems.

VOA: standard.2009.09.01

"We lost radio communication and that makes it very difficult in these conditions to know what's going on, " he told reporters after failing to follow up his 2010 and 2011 victories at Sepang.

CNN: Blowout brings Vettel back down to earth

"When we lost telephone service and radio communication, some officers were stranded on their rooftops for four to five days, stranded in areas around the water due to rising water or displaced into other units or divisions, " Riley said.

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Once Curiosity returns to normal, it'll only have a few days to work before a planetary alignment limits radio communication between Earth and Mars during most of next month.

NPR: Mars Rover Curiosity Stands Down After New Problem