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List Of United States Coast Guard Radio Stations
The United States Coast Guard maintains radio stations for communication between Coast Guard units, Coast Guard units and other government entities, and Coast Guard units and the general public. Most communications take place on the VHF marine bands. For long-range communications with aircraft, Coast Guard stations use shortwave single-sideband communications. Weather and safety of navigation forecasts involve facsimile as well as other modes over shortwave and mediumwave transmissions. According to the NTIA, the Coast Guard is the seventh-biggest user of radio spectrum in the United States. The U.S. Coast Guard maintains a network of VHF radio stations at its shore stations and on cutters and boats, as well as stations of the U.S. Coast Guard Auxiliary. In addition, the Coast Guard maintains a chain of high frequency (HF) and medium frequency (MF) radio stations that provide communications in the Atlantic and Pacific oceans, the Gulf of Mexico, and the Caribbean Sea. Coast Guar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, multi-mission service unique among the United States military branches for having a maritime law enforcement mission with jurisdiction in both domestic and international waters and a federal regulatory agency mission as part of its duties. It is the largest and most powerful coast guard in the world, rivaling the capabilities and size of most navies. The U.S. Coast Guard is a humanitarian and security service. It protects the United States' borders and economic and security interests abroad; and defends its sovereignty by safeguarding sea lines of communication and commerce across vast territorial waters spanning 95,000 miles of coastline and its Exclusive Economic Zone. With national and economic security depending upon open global trade a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Weather Service
The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the United States Department of Commerce, Department of Commerce, and is headquartered in Silver Spring, Maryland, Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970. The NWS performs its primary task through a collection of national and regional centers, and 122 local List of National Weather Service Weather Forecast Offices, Weather Forecast Offices (WFOs). As the NWS is an agency of the U.S. federal government, most o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Call Signs
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] |
National Telecommunications And Information Administration
The National Telecommunications and Information Administration (NTIA) is an agency of the United States Department of Commerce that serves as the President's principal adviser on telecommunications policies pertaining to the United States' economic and technological advancement and to regulation of the telecommunications industry. Among its stated goals are: * Working to ensure that all Americans have affordable phone and cable TV service. * Helping to bring the benefits of advanced telecommunications technologies to millions of Americans in rural and underserved urban areas through its information infrastructure grants. * Providing the hardware that enables public radio and television broadcasters to extend and maintain the reach of their programming. * Advocating competition and liberalization of telecommunications policies around the world. * Participating in international government-to-government negotiations to open markets for U.S. companies. * Negotiating with foreig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Department Of Commerce
The United States Department of Commerce is an executive department of the U.S. federal government concerned with creating the conditions for economic growth and opportunity. Among its tasks are gathering economic and demographic data for business and government decision making, and helping to set industrial standards. Its main purpose is to create jobs, promote economic growth, encourage sustainable development and block harmful trade practices of other nations.Steve Charnovitz, "Reinventing the Commerce Dept.", ''Journal of Commerce'', July 12, 1995. It is headed by the Secretary of Commerce, who reports directly to the President of the United States and is a member of the president's Cabinet. The Department of Commerce is headquartered in the Herbert C. Hoover Building in Washington, DC. History Organizational history The department was originally created as the United States Department of Commerce and Labor on February 14, 1903. It was subsequently renamed the Departm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfect Paul
DECtalk was a speech synthesizer and text-to-speech technology developed by Digital Equipment Corporation in 1983, based largely on the work of Dennis Klatt at MIT, whose source-filter algorithm was variously known as KlattTalk or MITalk. Uses ranged from interacting with the public to allowing those with speech disabilities to verbalize, include giving a public speech. History Announced December 1983, a trickle came February 1984; larger ''DECtalk'' quantities were delivered in March. They were standalone units that connected to any device with an asynchronous serial port. These units were also able to connect to the telephone system by having two telephone jacks. One connected to a phone line, the other to a telephone. The DECtalk units could recognize and generate any telephone touch tone. With that capability the units could be used to automate various telephone-related tasks by handling both incoming and outgoing calls. This included acting as an interface to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interval Signal
An interval signal, or tuning signal, is a characteristic sound or musical phrase used in international broadcasting, numbers stations, and by some domestic broadcasters, played before commencement or during breaks in transmission, but most commonly between programmes in different languages. It serves several purposes: * It helps a listener using a radio with an analog tuner to find the correct frequency. * It informs other stations that the frequency is in use. * It serves as a station identifier even if the language used in the subsequent broadcast is not one the listener understands. The practise began in Europe in the 1920s and 1930s and was carried over into shortwave broadcasts. The use of interval signals has declined with the advent of digital tuning systems, but has not vanished. Interval signals were not required on commercial channels in the United States, where jingles were used as identification. List of interval signals by station * Radiodifusión Argentina a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SITOR
SITOR (SImplex Teletype Over Radio) is a system for transmitting text messages. It was developed in the 1960s by Koninklijke TNT Post as an improvement over radioteletype (RTTY). Although it uses the same frequency-shift keying (FSK) modulation used by regular RTTY, SITOR uses error detection, redundancy, and/or retransmission to improve reliability. There are two SITOR modes: * SITOR-A is used for point to point links. SITOR-A uses automatic repeat request (ARQ) to gain reliability. If the receiver detects an error, it requests a retransmission. * SITOR-B is used for broadcast links. SITOR-B transmits each character in a message twice to gain reliability. If the receiver detects an error in the first character, it uses the copy. If both characters are garbled, the receiver won't know what was sent. * SITOR-B by definition uses forward error correction (FEC), versus ARQ for SITOR-A. SITOR sends 7-bit characters as a bit stream at 100 baud (which, in this case, is 100 bits per sec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Sideband
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver. Basic concept Radio transmitters work by mixing a radio frequency (RF) signal of a specific frequency, the carrier wave, with the audio signal to be broadcast. In AM transmitters this mixing usually takes place in the final RF amplifier (high level modulation). It is less common and much less efficient to do the mixing at low power and then amplify it in a linear ampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fort Tilden
Fort Tilden, also known as Fort Tilden Historic District, is a former United States Army installation on the coast in the New York City borough of Queens. Fort Tilden now forms part of the Gateway National Recreation Area, and is administered by the National Park Service. Fort Tilden Historic District is located on the Rockaway Peninsula, between Jacob Riis Park to the east and Breezy Point Tip to the west. All three of these sites are operated by the National Park Service. Since its decommissioning, the former installation has largely become a natural area of beaches, dunes and maritime forest. Most of the old military installations are abandoned, and military structures which formerly housed artillery (batteries) and ammunition (magazines) are covered in graffiti. A few buildings have been renovated and are used by local arts groups, and some large open areas are used as sports grounds. Atop one of the old batteries, Battery Harris East, a viewing platform has 360-degree v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortwave
Shortwave radio is radio transmission using shortwave (SW) radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (100 to 10 metres); above the medium frequency band (MF), to the bottom of the VHF band. Radio waves in the shortwave band can be reflected or refracted from a layer of electrically charged atoms in the atmosphere called the ionosphere. Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon. This is called skywave or "skip" propagation. Thus shortwave radio can be used for communication over very long distances, in contrast to radio waves of higher frequency, which travel in straight lines (line-of-sight propagation) and are limited by the visual horizon, about 64 km (40 miles). Shortwave broadcasts of radio programs played an important role in the early days of radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Maritime Distress Safety System
The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convention. It's a set of safety procedures, types of equipment, and communication protocols used for safety and rescue operations of the distressed ships, boats, and aircraft. It's supplemental to the International Convention on Maritime Search and Rescue (ICMSaR) adopted in 1979 and provides basis for the communication. GMDSS consists of several systems which are intended to perform the following functions: alerting (including position determination of the ship in distress) ships in the vicinity and ashore authorities, search and rescue coordination, locating (homing), maritime safety information broadcasts, general communications, and bridge-to-bridge communications. Specific radio carriage requirements depend upon the ship's area of operatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
