The Silence Periods - How 500 kHz Listened for the Dying Twice every hour, the busiest radio frequency at sea fell completely silent. It was not a fault. It was the system working exactly as designed - listening for someone whose life depended on being heard. The rule On 500 kHz, from minute 15 to 18 and 45 to 48 each hour, every station stopped transmitting. Radio rooms kept special clocks with those wedges painted red, and operators used the silence to listen for weak distress calls. Why it mattered Emergency transmitters ran on batteries and hope. Three minutes of worldwide quiet doubled their chances - a small discipline that saved uncountable lives before the watch ended in 1999. Translate any text to Morse code, play it as sound and download the audio free at: https://morsecodeworks.com/