This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.

这种通迅联系要靠21厘料波段，即每秒1420兆周的精确无线电频率。

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This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.

这种通迅联系要靠21厘料波段，即每秒1420兆周的精确无线电频率。

youdao