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Net Operation
A radio net is three or more radio stations communicating with each other on a common channel or frequency. A net is essentially a moderated conference call conducted over two-way radio, typically in half-duplex operating conditions. The use of half-duplex operation requires a very particular set of operating procedures to be followed in order to avoid inefficiencies and chaos. Nets operate either on schedule or continuously (continuous watch). Nets operating on schedule handle traffic only at definite, prearranged times and in accordance with a prearranged schedule of intercommunication. Nets operating continuously are prepared to handle traffic at any time; they maintain operators on duty at all stations in the net at all times. When practicable, messages relating to schedules will be transmitted by a means of signal communication other than radio. Net operations: * allow participants to conduct ordered conferences among participants who usually have common information needs or r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication Channel
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for information transfer of, for example, a digital bit stream, from one or several '' senders'' to one or several '' receivers''. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second. Communicating an information signal across distance requires some form of pathway or medium. These pathways, called communication channels, use two types of media: Transmission line (e.g. twisted-pair, coaxial, and fiber-optic cable) and broadcast (e.g. microwave, satellite, radio, and infrared). In information theory, a channel refers to a theoretical ''channel model'' with certain error characteristics. In this more general view, a storage device is also a communication channel, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiogram (message)
A radiogram is a formal written message transmitted by radio. Also known as a radio telegram or radio telegraphic message, radiograms use a standardized message format, form and radiotelephone and/or radiotelegraph transmission procedures. These procedures typically provide a means of transmitting the content of the messages without including the names of the various headers and message sections, so as to minimize the time needed to transmit messages over limited and/or congested radio channels. Various formats have been used historically by maritime radio services, military organizations, and Amateur Radio organizations. Radiograms are typically employed for conducting Record communications, which provides a message transmission and delivery audit trail. Sometimes these records are kept for proprietary purposes internal to the organization sending them, but are also sometimes legally defined as public records. For example, maritime Mayday/SOS messages transmitted by radio are def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tornado
A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward the surface of the Earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern. Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than , are about across, and travel several kilometers (a few miles) before dissipating. The most extreme tornadoes can attain wind speeds of more than , are more than in diameter, and stay on the ground for more than 100 k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skywarn
Skywarn (sometimes stylized as SKYWARN) is a program of the National Weather Service (NWS). Its mission is to collect reports of localized severe weather in the United States. These reports are used to aid forecasters in issuing and verifying severe weather watches and warnings and to improve the forecasting and warning processes and the tools used to collect meteorological data. Reports are also used by local emergency managers and public safety organizations. Skywarn consists of a network of severe storm spotters who observe weather conditions and make reports of severe weather to their local NWS offices. These spotters are regularly trained by personnel from the local NWS offices. In many areas, classes are conducted each spring in advance of the coming severe weather season. Many SKYWARN spotters use methods to communicate with one another during severe storm events. A notable example of this is through the use of amateur radio nets, which is still an important method since s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DXing
DXing is the hobby of receiving and identifying distant radio or television signals, or making two-way radio contact with distant stations in amateur radio, citizens' band radio or other two-way radio communications. Many DXers also attempt to obtain written verifications of reception or contact, sometimes referred to as " QSLs" or "veries". The name of the hobby comes from DX, telegraphic shorthand for "distance" or "distant". The practice of DXing arose during the early days of radio broadcasting. Listeners would mail "reception reports" to radio broadcasting stations in hopes of getting a written acknowledgement or a QSL card that served to officially verify they had heard a distant station. Collecting these cards became popular with radio listeners in the 1920s and 1930s, and reception reports were often used by early broadcasters to gauge the effectiveness of their transmissions. Although international shortwave broadcasts are on the decline, DXing remains popular among de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Amateur Radio Union
The International Amateur Radio Union (IARU) is an international confederation of national organisations that allows a forum for common matters of concern to amateur radio operators worldwide, and collectively represents matters to the International Telecommunication Union (ITU). The International Amateur Radio Union was founded in 1925 and, as of July 2021, it is composed of 172 national member societies. History Following an informal meeting in 1924 of representatives from France, Great Britain, Belgium, Switzerland, Italy, Spain, Luxembourg, Canada, and the United States, a plan was formulated to hold an International Amateur Congress in Paris, France, in April 1925. This Congress was held for the purpose of founding an international amateur radio organization. The Congress was attended by representatives of 23 countries in Europe, Americas, and Asia. A constitution for the IARU was adopted on April 17, and the formation of the International Amateur Radio Union was ratified on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incident Command Post
According to the National Incident Management System (NIMS), and the Incident Command System (ICS), the incident command post (ICP) is one of five predesignated temporary facilities and signifies the physical location of the tactical-level, on-scene incident command and management organization. It typically comprises the incident commander and immediate staff and may include other designated incident management officials and responders from federal, state, local, and tribal agencies, as well as private-sector, nongovernmental, and volunteer organizations. Typically, the ICP is located at or in the immediate vicinity of the incident site and is the focus for the conduct of direct, on-scene control of tactical operations. Incident planning is also conducted at the ICP; an incident communications center also would normally be established at this location. The ICP may be collocated with the incident base, if the communications requirements can be met. The ICP may perform local emergency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Civil Air Patrol
Civil Air Patrol (CAP) is a congressionally chartered, federally supported non-profit corporation that serves as the official civilian auxiliary of the United States Air Force (USAF). CAP is a volunteer organization with an aviation-minded membership that includes people from all backgrounds, lifestyles, and occupations. The program is established as an organization by Title 10 of the United States Code and its purposes defined by Title 36. Membership in the organization consists of cadets ranging from 12 to just under 21 years of age, and senior members 18 years of age and up. These two groups each have the opportunity to participate in a wide variety of pursuits; the cadet program contributes to the development of the former group with a structured syllabus and an organization based upon United States Air Force ranks, while the older members serve as instructors, supervisors, and operators. Most members wear uniforms while performing their duties, however there is a category ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Traffic System
The National Traffic System (NTS) is an organized network of amateur radio operators sponsored by the American Radio Relay League for the purpose of relaying messages throughout the U.S. and Canada. During normal times, these messages are routine greetings ("Happy birthday Aunt Mary") and keep the system well oiled and the operators trained so that everything works when needed. When there is an emergency or disaster NTS works closely with the Amateur Radio Emergency Service to provide emergency communications. The most common type of disaster-related messages are "health and welfare" inquiries and notifications into and out of the area affected by the disaster. In time of disaster, it is easy to expand the system by simply creating additional meeting times for the nets with high volume, or by setting up a specific "trunk line" between two points. History Traffic passing by formal relay (via amateur radio) originates from the founding of the American Radio Relay League. The NT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Auxiliary Radio System
The Military Auxiliary Radio System (MARS) is a United States Department of Defense sponsored program, established as a separately managed and operated program by the United States Army, and the United States Air Force. The United States Navy-Marine Corps program closed in 2015. The program is a civilian auxiliary consisting primarily of licensed amateur radio operators who are interested in assisting the military with communications on a regional and national level when access to traditional forms of communication may no longer be available. The MARS programs also include active duty, reserve, and National Guard units; and Navy, Marine Corps units. MARS has a long history of providing worldwide auxiliary emergency communications during times of need. The combined two-service MARS programs (Army, and Air Force), volunteer force of over 3,000 dedicated and skilled amateur radio operators provide the backbone of the MARS program. The main benefit of MARS membership is enjoying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverted Pyramid (journalism)
The inverted pyramid is a metaphor used by journalists and other writers to illustrate how information should be prioritised and structured in prose (e.g., a news report). It is a common method for writing news stories and has wide adaptability to other kinds of texts, such as blogs, editorial columns and marketing factsheets. It is a way to communicate the basics about a topic in the initial sentences. The inverted pyramid is taught to mass communication and journalism students, and is systematically used in English-language media. The inverted or upside-down pyramid can be thought of as a triangle pointing down. The widest part at the top represents the most substantial, interesting, and important information that the writer means to convey, illustrating that this kind of material should head the article, while the tapering lower portion illustrates that other material should follow in order of diminishing importance. It is sometimes called a summary news lead style, or bottom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
