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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Attaching radio devices to it is difficult, and visual sightings are too unreliable to give real insight into its behavior.

给它安装无线电设备是很困难的，而且仅凭肉眼观测也太不可靠，无法对它的行为进行确切的观察。

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As a person with visual impairment himself, radio also provided an essential source of information.

作为一名视觉障碍人士，广播为他提供了重要的信息来源。

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To use the MINI Connected App, owners need to specify their MINI with the MINI Visual Boost radio or MINI navigation system, plus the MINI Connected option.

ENGADGET: Mini Cooper Connected app adjusts music based on driving style, stops when airbags deploy

Paul Harvey, who died recently at age 90, was to radio what Norman Rockwell was to visual arts.

FORBES: An American Giant

Lifted from Picasso's drawings of bulls in a few penstrokes which were nothing if not ergonomic the radio is more than an ingenious visual flourish.

ECONOMIST: American blobjectivity