Authorities say the couple also used short wave radio to take orders from Havana and to transmit information.

VOA: standard.2009.06.06

If you hook a radio wave up with a radio, you can tell the radio wave was there because what the radio is doing?

如果你用收音机检测无线电波，你可以知道无线电波在那,因为收音机在干什么？

耶鲁公开课 - 死亡课程节选

You can't smell a radio wave.

你闻不到无线电波。

耶鲁公开课 - 死亡课程节选

You can't touch a radio wave.

你摸不到无线电波。

耶鲁公开课 - 死亡课程节选

You don't see a radio wave.

你看不见无线电波。

耶鲁公开课 - 死亡课程节选