Modes of Transmission
These stations broadcast navigation and marine safety messages through several means, including Navigational Telex transmissions on 518 kHz; facsimile transmissions of National Weather Service charts; single sideband transmissions; and Simplex Teletype Over Radio SITOR narrow-band direct-printing broadcasts. In the 1960s through the 1980s, these transmissions were broadcast live, with the interval signal of "Semper Paratus"; however, now, using Voice Broadcast Automation (VOBRA), a computerized voice ("Perfect Paul") reads the voice messages.
NAVTEX transmissions are identified by the last letter of the callsign of the station. Each station transmits a NAVTEX broadcast six times a day, including two rebroadcasts of the general forecast. A NAVTEX broadcast includes maritime navigation warnings, weather forecasts, ice warnings, Gulf Stream locations, radio navigation information, rescue messages, and marine advisorys. Each station has 2 NAVTEX transmitters.
Besides broadcast messages, Coast Guard stations handle direct traffic between aircraft, cutters, boats, and shore stations on VHF, MF, and HF frequencies, including the HF Data Link encrypted e-mail system and Digital Selective Calling (DSC), which uses radio telephone to send digitally-encrypted signals to either one receiver or a group or receivers.
Read more about this topic: U.S. Coast Guard Radio Stations
Famous quotes containing the words modes of and/or modes:
“I cannot beat off
Invincible modes of the sea, hearing:
Be a man my son by God.
He turned again
To the purring jet yellowing the murder story,
Deaf to the pathos circling in the air.”
—Allen Tate (1899–1979)
“Men and women are brothers and sisters; they are not of different species; and what need be obtained to know both, but to allow for different modes of education, for situation and constitution, or perhaps I should rather say, for habits, whether good or bad.”
—Samuel Richardson (1689–1761)