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Amateur Radio Net
An amateur radio net, or simply ham net, is an " on-the-air" gathering of amateur radio operators. Most nets convene on a regular schedule and specific frequency, and are organized for a particular purpose, such as relaying messages, discussing a common topic of interest, in severe weather (for example, during a Skywarn activation), emergencies, or simply as a regular gathering of friends for conversation. Net operation Nets operate more or less formally depending on their purpose and organization. Groups of nets may organize and operate in collaboration for a common purpose, such as to pass along emergency messages in time of disaster. One such system of nets is the National Traffic System (NTS), organized and operated by members of the American Radio Relay League (ARRL) to handle routine and emergency messages on a nationwide and local basis. Formal operation A formal, or ''directed'' net has a single ''net control station '' (NCS) that manages its operation for a given se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On The Air
On the Air may refer to: *On the Air (album), ''On the Air'' (album), 1984, by Billy Preston *On the Air (TV series), ''On the Air'' (TV series), an American sitcom *On the Air (film), ''On the Air'' (film), a 1934 British musical comedy *On the Air (band), an English rock band * "On the Air", a song by Peter Gabriel from his Peter Gabriel (1978 album), second solo album See also * ''On the Aire'', a current affairs programme in Leeds, England * On air (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etymology Of Ham Radio
''Ham radio'' is a popular term for amateur radio, derived from "ham" as an informal name for an amateur radio operator. The use first appeared in the United States during the opening decade of the 20th century—for example, in 1909, Robert A. Morton reported overhearing an amateur radio transmission which included the comment: "Say, do you know the fellow who is putting up a new station out your way? I think he is a ham." However, the term did not gain widespread usage in the United States until around 1920, after which it slowly spread to other English-speaking countries. Etymology At the turn of the 20th century, the terms "ham" and "plug" were used by landline telegraphers to describe an operator "who lacks ability" or who had poor or "ham fisted" skills. By 1881, it had been alleged by telegrapher unions and trade groups that companies were employing "ham" operators who were negligent or incompetent. These unskilled operators were described as either drinking alcohol w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio On The International Space Station
Amateur Radio on the International Space Station (ARISS), operating in the Amateur-satellite service, is a project sponsored by various entities and carried out by astronauts and cosmonauts on the International Space Station who also have an amateur radio license. The program was previously called SAREX, the Space Amateur Radio Experiment, and before that the Shuttle Amateur Radio Experiment. In 2011, Kenwood Electronics launched an advertising campaign capitalizing on the fact that their TM-D700A transceiver is currently in use on the ISS. Amateur radio operators all over the world are able to speak directly to astronauts/cosmonauts via their handheld, mobile, or home radio stations. Low power radios and small antennas can be used to establish communications. It is also possible to send digital data to the space station via laptop computers hooked up to the same radio and antenna, similar to an email communication, except that it uses radio frequencies instead of telep ... [...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] |
ARRL Radiogram
An ARRL radiogram is an instance of formal written message traffic routed by a network of amateur radio operators through traffic nets, called the National Traffic System (NTS). It is a plaintext message, along with relevant metadata (headers), that is placed into a traffic net by an amateur radio operator. Each radiogram is relayed, possibly through one or more other amateur radio operators, to a radio operator who volunteers to deliver the radiogram content to its destination. Form overview Radiogram forms facilitate a standard protocol between amateur radio operators, allowing much faster relay of formal messages. They do this by always having the message headers in a certain order, allowing operators to read and understand the headers without explicit verbal labels. This is especially important in hectic and stressful environments such as during a disaster, when many parties call upon radio operators to quickly transfer messages in and out of the affected areas. A typica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Vintage Amateur Radio
Vintage amateur radio is a subset of amateur radio hobby where enthusiasts collect, restore, preserve, build, and operate amateur radio equipment from bygone years, such as those using vacuum tube technology. Popular modes of operation include speaking over amplitude modulation (AM), and communicating using Morse code through continuous wave (CW) radiotelegraphy. Some enthusiasts have interest in owning, restoring and operating vintage military and commercial radio equipment such as those from 1940s to 1960s. Some undertake to construct their own gear, known in ham slang as homebrewing, using vintage parts and designs. A number of amateur radio clubs and organizations sponsor contests, events, and swap meets that cater to this specialized aspect of the hobby. Appeal Vintage radio enthusiasts contend that the precise digital frequency displays and state-of-the-art, microprocessor-based features of modern amateur equipment lacks the aesthetic appeal and "soul" of amateur electroni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Frequency Allocations
Amateur radio frequency allocation is done by national telecommunication authorities. Globally, the International Telecommunication Union (ITU) oversees how much radio spectrum is set aside for amateur radio transmissions. Individual amateur stations are free to use any frequency within authorized frequency ranges; authorized bands may vary by the class of the station license. Radio amateurs use a variety of transmission modes, including Morse code, radioteletype, data, and voice. Specific frequency allocations vary from country to country and between ITU regions as specified in the current ITU HF frequency allocations for amateur radio. The list of frequency ranges is called a ''band allocation'', which may be set by international agreements, and national regulations. The modes and types of allocations within each frequency band is called a bandplan; it may be determined by regulation, but most typically is set by agreements between amateur radio operators. National authorities ... [...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] |
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] |
ARRL
The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of Hartford, Connecticut. The ARRL represents the interests of amateur radio operators before federal regulatory bodies, provides technical advice and assistance to amateur radio enthusiasts, supports a number of educational programs and sponsors emergency communications service throughout the country. The ARRL has approximately 161,000 members. In addition to members in the US, the organization claims over 7,000 members in other countries. The ARRL publishes many books and a monthly membership journal called ''QST''. The ARRL is the primary representative organization of amateur radio operators to the US government. It performs this function by lobbying the US Congress and the Federal Communications Commission. The ARRL is also the internati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Round-robin Scheduling
Round-robin (RR) is one of the algorithms employed by process and network schedulers in computing.Guowang Miao, Jens Zander, Ki Won Sung, and Ben Slimane, Fundamentals of Mobile Data Networks, Cambridge University Press, , 2016. As the term is generally used, time slices (also known as time quanta) are assigned to each process in equal portions and in circular order, handling all processes without priority (also known as cyclic executive). Round-robin scheduling is simple, easy to implement, and starvation-free. Round-robin scheduling can be applied to other scheduling problems, such as data packet scheduling in computer networks. It is an operating system concept. The name of the algorithm comes from the round-robin principle known from other fields, where each person takes an equal share of something in turn. Process scheduling To schedule processes fairly, a round-robin scheduler generally employs time-sharing, giving each job a time slot or ''quantum'' (its allowance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
