international radio silence

international radio silence

[¦in·tər¦nash·ən·əl ¦rād·ē·ō ¦sī·ləns] (communications) Three-minute periods of radio silence, on the frequency of 500 kilohertz only, commencing 15 and 45 minutes after each hour, during which all marine radio stations must listen on that frequency for distress signals of ships and aircraft.