Amateur radio

From Megawiki

Amateur radio, often called ham radio, is a hobby enjoyed by about 3 million people[1] throughout the world. An amateur radio operator, ham, or radio amateur uses two-way radio to communicate with other radio amateurs for public service, recreation and self-improvement.

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History

Throughout its history, amateur radio enthusiasts have made significant contributions to science, engineering, industry, and social services. The economic and social benefit derived from research by amateur radio operators has founded new industries, built economies, empowered nations, and saved lives.

The birth of amateur radio and radio in general has mostly been associated with the original experiments by Heinrich Rudolf Hertz in 1888 and later experiments by Guglielmo Marconi from 1895 to 1899 to send a wireless message across the English Channel and the first transatlantic transmission in 1902[2]. There are many contenders as the inventor of radio, that honor has been disputed between not only Hertz and Marconi, but also Amos Dolbear, Reginald Fessenden, James Clerk Maxwell, Sir Oliver Lodge, Mahlon Loomis, Nathan Stubblefield[3] and Alexander Popov[4], and Nikola Tesla[5].

In the period following Marconi's experiments (1900-1908) many people throughout the world began experimenting with radio. Communications were made in Morse Code by use of spark gap transmitters or high frequency alternators. These first amateur radio operators are the roots of the modern international phenomenon of amateur radio.

In 1912, the United States Congress passed the Radio Act of 1912 [2] which also restricted private stations to wavelengths of 200 meters or shorter (1500 kHz or higher).[6] These frequencies at the time were generally considered useless and the number of radio hobbyists dropped by as much as an estimated 88%.[7]) By this time, the term "ham" for an amateur radio operator was well established, the origins of which are obscure.[8] [9] [10]

By 1917, World War I had put a stop to amateur radio. In the United States, the Congress had actually ordered all amateur radio operators to cease operation and even dismantle their equipment.[11]

A challenge was issued by American hams to their counterparts in the United Kingdom in 1921 to receive radio contacts from across the Atlantic. Soon, many American stations were beginning to be heard in the UK, shortly followed by a UK amateur being heard in the US by December of 1922. The first two way contact between the UK and USA was in December, 1923. between London and West Hartford, CT.[12]

The International radiotelegraph conference was held in Washington, DC, USA in 1927-28.[2] At the conference, the familiar amateur radio bands of 80, 40, 20 & 10 meters were established by treaty and international radio callsign prefixes were devised.

During the Nazi occupation of Poland, Fr. Maximilian Kolbe, SP3RN was arrested by the Nazis as a priest.[13] The Nazis believed his amateur radio activities were somehow involved in espionage[14] and he was transferred to Auschwitz on the 28th of May, 1941. After some prisoners escaped in 1941, The Nazis ordered that 10 prisoners be killed in retribution. Fr. Kolbe was martyred when he volunteered to take the place of one of the condemned men. On the 10th of October, 1982 he was canonized by Pope John Paul II as Saint Maximilian Kolbe, Apostle of Consecration to Mary and declared a Martyr of charity[13]. He is considered the Patron saint of Amateur radio operators.[14]

Again during World War II, as it had done during the first World War, the United States Congress suspended all amateur radio operations[6] . With most of the American amateur radio operators in the armed forces at this time, the US government created the War emergency radio service which would remain active through 1945. After the War the amateur radio service began operating again.

In 1961 the first orbital satellite carrying amateur radio (OSCAR) was launched. Oscar I would be the first of a series of amateur radio satellites created throughout the world. [15]

The World administrative radio conference met in Geneva, Switzerland in 1979. Among the many topics covered at this meeting was the creation of three new amateur radio bands: 30 meters, 17 meters and 12 meters[16]. Today, these three bands are referred to collectively as the WARC bands by amateur radio operators.

During the Falklands War in 1982, Argentine forces seized control of the phones and radio network on the islands and had cut off communications with London. Scottish amateur radio operator Les Hamilton, GM3ITN[17][18] was able to relay crucial information from fellow hams Bob McLeod and Tony Pole-Evans on the islands to British military intelligence in London the details of troop deployment, bombing raids, radar bases and military activities.[19]

Major contributions to communications in the fields of automated message systems and packet radio were made by amateur radio operators throughout the 1980s. These computer controlled systems were used for the first time to distribute communications during and after disasters.[2]

By international agreement in the past, amateur radio operators were required to have a qualification endorsement of Morse Code proficiency to use frequencies below 30 MHz. In 2003 the World radiocommunications conference (WRC) met in Geneva, Switzerland, and Morse code is no longer an internationally required qualification for an amateur radio license.[20] This does not preclude any licensing authority from requiring the proficiency of Morse code to obtain an amateur radio license, however countries are no longer obliged by international treaty to require Morse code proficiency. Current rules in the United States[21] require some Morse code proficiency to allow operation on frequencies below 30 MHz. Proceedings by the FCC are currently underway regarding whether the requirement will be kept. Discussions regarding whether it should engender lively debate among amateur radio operators.

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Amateur radio activities and practices

Amateur radio operators enjoy personal two-way communications with friends, family members, and complete strangers, all of whom must also be licensed. They support the larger public community with emergency and disaster communications. Increasing a person's knowledge of electronics and radio theory as well as radio contesting are also popular aspects of amateur radio.

Radio amateurs use a variety of modes of transmission to communicate with one another. Voice transmissions are the most common way hams communicate with one another, with some types of emission such as frequency modulation (FM) offering high quality audio for local operation where signals are strong, and others such as Single-sideband modulation|single side band (SSB) offering more reliable communications when signals are marginal and using smaller amounts of bandwidth.

Radiotelegraphy using Morse code remains surprisingly popular, particularly on the shortwave bands and for experimental work on the microwave bands, with its inherent signal-to-noise ratio advantages. Morse, using internationally agreed code groups, can also facilitate communications between amateurs who do not share a common language. Radiotelegraphy is also popular with home constructors as CW-only transmitters are simple to construct when compared to voice transmitters.

The explosion in personal computing power has led to a boom in digital modes such as radio teletype, which a generation ago required cumbersome and expensive specialist equipment. Hams led in the development of packet radio, which has since been augmented by more specialized modes such as PSK31 which is designed to facilitate real-time, low-power communications on the shortwave bands. Other modes, such as the WSJT suite, are aimed at extremely marginal propagation modes including meteor scatter and moonbounce or Earth-Moon-Earth (EME).

Similarly, fast scan amateur television, once considered rather esoteric, has exploded in popularity thanks to cheap camcorders and good quality video cards in home computers. Because of the wide bandwidth and stable signals required, it is limited in range to at most 100 km (about 62 miles) in normal conditions.

The modes noted above are typically used in direct, radio-to-radio communication. On VHF and higher frequencies, automated relay stations, or repeaters, are used to increase range. Repeaters are usually located on the top of a mountain or tall building. A repeater allows the radio amateur to communicate over hundreds of square miles using only a relatively low power hand-held transceiver. Repeaters can also be linked together, either by use of other amateur radio bands, by wireline, or, increasingly via the Internet.

While many hams just enjoy talking to friends, others pursue interests such as providing communications for a Community emergency response team (CERT); antenna theory; communication viaamateur satellites; disaster response; severe weather spotting; DX communication over thousands of miles using the ionosphere to refract radio waves; the Internet Radio Linking Project (IRLP) which is a composite network of radio and the Internet; Automatic Position Reporting System (APRS), which is a system of remote positioning that uses GPS; Contesting; the sport of Amateur Radio Direction Finding; High Speed Telegraphy; or low-power operation.

Most hams have a room or area in their home which is dedicated to their radio and ancillary test equipment, known as the "shack" in ham slang.

Many hams enjoy meeting each other in person at events held in various locations. These annual events are generally known as a hamfest with the largest being held in Dayton Ohio.

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Getting started

Many people get started in amateur radio by finding a local club. Clubs can provide information about licensing in their respective area, local operating practices and technical advice. (See Wikipedia's Category: Amateur radio organizations)

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When licensed

After licensing, a radio amateur is typically issued a callsign by their local government. This callsign is unique to the operator and is often a source of pride. The holder of a callsign uses it on the air to legally identify the operator or station during any and all radio communication.

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Privileges of the amateur

In contrast to most commercial and personal radio services, most radio amateurs are not restricted to using type-approved equipment, allowing them to home-construct or modify equipment in any way so long as they meet national and international standards on spurious emissions.

As noted, radio amateurs have access to frequency allocations throughout the RF spectrum, enabling choice of frequency to enable effective communication whether across a city, a region, a country, a continent or the whole world regardless of season or time day or night. The shortwave bands, or HF, can facilitate worldwide communication, the VHF and UHF bands offer excellent regional communication, and the broad microwave bands have enough space, or bandwidth, for television transmissions and high-speed data networks.

Although permitted power levels are moderate by commercial standards, they are sufficient to enable cross-continental communication even with the least effective antenna systems, and world-wide communications at least occasionally even with moderate antennas. Power limits vary from country to country,for example, 1.5 kilowatts in the United States.

Some suggest that the amateur portion of the radio spectrum is like a national park: something like the Yosemite of natural phenomena. Through the licensing requirement, radio amateurs become like trained national park guides and backpackers. Where the backpackers and guides know about the beauty of the parks as well as the rules of engagement with wildlife in the park system, radio amateurs learn to appreciate and respect the beauty of the very limited electromagnetic space and the rules of engagement of human interaction within that space. In contrast, all of humanity benefits from the radio spectrum's existence, although it can not actually be seen.

In the United States, the Federal Communications Commission licenses operators in the Amateur Service as part of a mission that includes radio experimentation, public service, and the maintaining of a trained pool of technically-oriented operators. In exchange for learning the information needed to pass the federal test, licensed operators are allowed to use some 1300 distinct modes of communications, at power levels ranging from microwatts to thousands of watts, effective radiated power.

A distinguishing privilege of amateur radio is the ability to use a Variable-frequency oscillator (VFO) for controlling the frequencies of communications. Usually, the only other radio services granted the use of a VFO are military. All others, (aircraft; police; fire; Citizens' band; and business radio services,) are restricted to designated channelized frequencies. The privilege to use a VFO is granted to Amateur radio operator only after he or she has demonstrated the understanding of the frequency ranges under which the license is granted by taking an examination at the time of licensing. Amateur radio operators also are allowed to operate "out of band" in certain situations. For example, facilitating emergency communications or participation in the Military Affiliate Radio System (MARS) to exchange radio telegrams on military frequencies.

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Governance and amateur radio societies

The International Telecommunication Union (ITU) governs the allocation of communications frequencies world-wide, with participation by each nation by representation from their communications regulation authority. National communications regulators have some liberty to restrict access to these frequencies, or to award additional allocations as long as radio services in other countries do not suffer interference.

In some countries, specific emission types are restricted to certain parts of the radio spectrum, and in most other countries, International Amateur Radio Union (IARU) member societies adopt voluntary plans to concentrate modes of transmission in specific frequency allocations within IARU guidelines, to ensure most effective use of available spectrum.

Many countries have their own national (non-government) amateur radio society that coordinates with the communications regulation authority for the benefit of all Amateurs. The oldest of these societies is the Wireless Institute of Australia, formed in 1910; other notable societies are the Radio Society of Great Britain, the American Radio Relay League, and Radio Amateurs of Canada.


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Publications

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