|
Maritime Call Sign
Maritime call signs are call signs assigned as unique identifiers to ships and boats. All radio transmissions must be individually identified by the call sign. Merchant and naval vessels are assigned call signs by their national licensing authorities. History One of the earliest applications of radiotelegraph operation, long predating broadcast radio, were marine radio stations installed aboard ships at sea. In the absence of international standards, early transmitters constructed after Guglielmo Marconi's first trans-Atlantic message in 1901 were issued arbitrary two-letter calls by radio companies, alone or later preceded by a one-letter company identifier. These mimicked an earlier railroad telegraph convention where short, two-letter identifiers served as Morse code abbreviations to denote the various individual stations on the line (for instance, AX could represent Halifax). "N" and two letters would identify U.S. Navy; "M" and two letters would be a Marconi station. On Apr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Call Sign
In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or even cryptographically encoded to disguise a station's identity. The use of call signs as unique identifiers dates to the landline railroad telegraph system. Because there was only one telegraph line linking all railroad stations, there needed to be a way to address each one when sending a telegram. In order to save time, two-letter identifiers were adopted for this purpose. This pattern continued in radiotelegraph operation; radio companies initially assigned two-letter identifiers to coastal stations and stations onboard ships at sea. These were not globally unique, so a one-letter company identifier (for instance, 'M' and two letters as a Marconi station ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guglielmo Marconi
Guglielmo Giovanni Maria Marconi, 1st Marquis of Marconi (; 25 April 187420 July 1937) was an Italians, Italian inventor and electrical engineering, electrical engineer, known for his creation of a practical radio wave-based Wireless telegraphy, wireless telegraph system. This led to Marconi being credited as the inventor of radio, and he shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy".Guglielmo Marconi: The Nobel Prize in Physics 1909 . nobelprize.org Marconi was also an entrepreneur, businessman, and founder of Marconi Company, The Wireless Telegraph & Signal Company in the United Kingdom of Great Britain and Ireland, United Kingdom in 1897 (which became the Marconi Com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean split at about 8°N. Scientific explorations of the A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of the inventors of the telegraph. International Morse code encodes the 26 basic Latin letters through , one accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals ( prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration is the basic unit of time measurement in Morse code transmission. The duration of a ''dah'' is three times the duration of a ''dit''. Each ''dit'' or ''dah'' within an encoded character is followed by a period of signal absence, called a ''space'', equal to the ''dit'' duration. The letters of a word are separated by a space of duration equal to three ''dits'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marconi Station
A list of early wireless telegraphy radio stations of the Marconi Wireless Telegraph Co. Guglielmo Marconi developed the first practical radio transmitters and receivers between 1895 and 1901. His company, the Marconi Wireless Telegraph Co, started in 1897, dominated the early radio industry. During the first two decades of the 20th century the Marconi Co. built the first radiotelegraphy communication stations, which were used to communicate with ships at sea and exchange commercial telegram traffic with other countries using Morse code. Many of these have since been preserved as historic places. Types of station The first radio transmitters could not transmit audio (sound) like modern AM and FM transmitters, and instead transmitted information by radiotelegraphy; the transmitter was turned on and off rapidly using a switch called a telegraph key, creating different length pulses of radio waves ("dots" and "dashes") which spelled out text messages in Morse code. Marc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flag Of Convenience
Flag of convenience (FOC) is a business practice whereby a ship's owners register a merchant ship in a ship register of a country other than that of the ship's owners, and the ship flies the civil ensign of that country, called the flag state.Bernaert, 2006, p. 104. The term is often used pejoratively, and although common, the practice is sometimes regarded as contentious. Each merchant ship is required by international law to be registered in a registry created by a country,ICFTU et al., 2002, p. 7. and a ship is subject to the laws of that country, which are used also if the ship is involved in a case under admiralty law. A ship's owners may elect to register a ship in a foreign country so as to avoid the regulations of the owners' country, which may, for example, have stricter safety standards. They may also select a jurisdiction to reduce operating costs, avoiding higher taxes in the owners' country and bypassing laws that protect the wages and working conditions of marin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WSB (AM)
WSB (750 kHz) is a commercial AM radio station in Atlanta, Georgia. It airs a news/talk radio format, simulcast on Doraville-licensed WSBB-FM. WSB is the flagship station for Cox Media Group; in addition to WSB and WSBB-FM, it owns three other Atlanta radio stations and Atlanta's ABC Television Network affiliate, WSB-TV. From 1939 to 2019, WSB was owned by Cox Enterprises along with the '' Atlanta Journal-Constitution'' daily newspaper; the station had been established by the ''Journal'' in 1922. The station's studios and offices are located at the WSB Television and Radio Group building on West Peachtree Street in Midtown Atlanta, which is shared with its television and radio partners. WSB transmits with 50,000 watts of nondirectional power, the highest permitted by the Federal Communications Commission (FCC) for commercial AM stations. WSB is a clear-channel Class A station. The transmitter and radiating tower are located seven miles (11 kilometers) northeast of Atlan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Atlanta Journal
''The Atlanta Journal-Constitution'' is the only major daily newspaper in the metropolitan area of Atlanta, Georgia. It is the flagship publication of Cox Enterprises. The ''Atlanta Journal-Constitution'' is the result of the merger between ''The Atlanta Journal'' and ''The Atlanta Constitution''. The two staffs were combined in 1982. Separate publication of the morning ''Constitution'' and the afternoon ''Journal'' ended in 2001 in favor of a single morning paper under the ''Journal-Constitution'' name. The ''Atlanta Journal-Constitution'' has its headquarters in the Atlanta suburb of Dunwoody, Georgia. It was formerly co-owned with television flagship WSB-TV and six radio stations, which are located separately in midtown Atlanta; the newspaper remained part of Cox Enterprises, while WSB became part of an independent Cox Media Group. ''The Atlanta Journal'' ''The Atlanta Journal'' was established in 1883. Founder E. F. Hoge sold the paper to Atlanta lawyer Hoke Smith in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maritime Mobile Service Identity
A Maritime Mobile Service Identity (MMSI) is effectively a maritime object's international ''maritime telephone number'', a temporarily assigned UID, issued by that object's current flag state, (unlike an IMO, which is a global forever UID). An MMSI comprises a series of nine digits, consisting Maritime Identification Digits(country-codes), concatenated with a specific identifier. Whenever an object is re-flagged, a new MMSI must be assigned. A 'maritime object' could be anything which requests an MMSI identifier. e.g. a vessel, fixed offshore installation, mobile unit, maritime aircraft, coast station, etc. Communications may be routed to 'individual objects', or to 'groups of objects'. A group call to objects can be based on an object's - locale, owner/operator/fleet, type, etc. or combinations thereof. MMSI are formed in such a way that the identity or part thereof can be used by telephone and telex subscribers connected to the general telecommunications network to call a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pan-pan
The radiotelephony message PAN-PAN is the international standard urgency signal that someone aboard a boat, ship, aircraft, or other vehicle uses to declare that they have a situation that is urgent, but for the time being, does not pose an immediate danger to anyone's life or to the vessel itself. This is referred to as a state of "urgency". This is distinct from a mayday call (distress signal), which means that there is imminent danger to life or to the continued viability of the vessel itself. Radioing "pan-pan" informs potential rescuers (including emergency services and other craft in the area) that an urgent problem exists, whereas "mayday" calls on them to drop all other activities and immediately begin a rescue. The exact representation of PAN in Morse code is the urgency signal XXX, which was first defined by the International Radiotelegraph Convention of 1927. Etymology As with "mayday" (from ''venez m'aider'', "come help me"), the urgency signal pan-pan derives from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> The Atlanta Journal")