Maritime practice has shifted from rescue radios on 500 kHz distress frequency ( which is no longer officially monitored ) to the Global Maritime Distress Safety System, which includes use of the Cospas-Sarsat system and other measures, including radar transponders and hand-held marine VHF radios.
12.
The report's recommendations on the regulation of wireless telegraphy were implemented in the form of the Radio Act of 1912, which mandated that all radio stations in the US be licensed by the federal government, as well as mandating that seagoing vessels continuously monitor distress frequencies.
13.
The signal, " Emergency stop ", to warn the other vessels was immediately given by searchlight, and the message . " " Wilkes " aground do not know which side " was broadcast on the TBS . The words, " " Wilkes " aground ", were also broadcast on the distress frequency.
14.
Despite the switch to 406 MHz, pilots and ground stations are encouraged to continue to monitor for transmissions on the emergency frequencies, as many 406 beacons are also equipped with 121.5 " homers . " Furthermore, the 121.5 MHz frequency continues to be used as a voice distress frequency ( especially in aviation ).
15.
The captain of another aircraft attempted to reach the crew of Flight 370 " just after [ 01 : 30 ] " using the international distress frequency to relay Vietnamese air traffic control's request for the crew to contact them; the captain said he was able to establish contact, but only heard " mumbling " and static.
16.
During the attack on the USS Liberty, the Israelis used unmarked aircraft, jammed the ship's radios on both U . S . Navy tactical and International Maritime Distress frequencies, destroyed by machine-gun fire life rafts that had been dropped over the side by crewmen preparing to abandon the ship, and refused to offer immediate aid upon cessation of hostilities.
17.
:: Although Finlay directed you to the relevant article, I think a brief answer here is in order : The red areas mark the times during which radio stations using the international distress frequency of 500 kHz should stop transmitting and listen to see if any distress calls are being sent .-- talk ) 21 : 37, 30 June 2012 ( UTC)
18.
The official lower limit remained at 550 kHz, as it was not possible to add stations at the bottom of the broadcast band due to the need to protect 500 kHz a maritime international distress frequency from interference . ( Although operation on 540 kHz was not covered by the Agreement, unofficially it became an additional Canadian clear channel frequency .)
