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Author Topic: HAM - Amatuer Radio according to Wikipedia  (Read 453 times)
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« on: May 12, 2009, 01:28:14 PM »

HAM - Amatuer Radio according to Wikipedia

Thought this may be useful for those of us that want to learn more about HAM.

From Wikipedia, copy and paste, link to the full thing on the bottom of this post:


Amateur radio, often called ham radio, is both a hobby and a service in which participants, called "hams," use various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training.[1]

Amateur radio operators enjoy personal (and often worldwide) wireless communications with each other and are able to support their communities with emergency and disaster communications if necessary, while increasing their personal knowledge of electronics and radio theory. An estimated six million people throughout the world are regularly involved with amateur radio.[2]

The term "amateur" is not a reflection on the skills of the participants, which are often quite advanced; rather, "amateur" indicates that amateur communications are not allowed to be made for commercial or money-making purposes.

Though its origins can be traced to at least the late 1800s, amateur radio, as practiced today, did not begin until the early 1900s. The first listing of amateur radio stations is contained in the First Annual Official Wireless Blue Book of the Wireless Association of America in 1909.[3] This first radio callbook lists wireless telegraph stations in Canada and the United States, including eighty-nine amateur radio stations. As with radio in general, the birth of amateur radio was strongly associated with various amateur experimenters and hobbyists. Throughout its history, amateur radio enthusiasts have made significant contributions to science, engineering, industry, and social services. Research by amateur radio operators has founded new industries[4], built economies[5], empowered nations[6], and saved lives[7] in times of emergency.

Amateur Radio operators use various modes of transmission to communicate. Voice transmissions are most common, with some, such as frequency modulation (FM) offering high quality audio, and others, such as single sideband (SSB) offering more reliable communications when signals are marginal and bandwidth is restricted.

Radiotelegraphy using Morse code is an activity dating to the earliest days of radio. Technology has moved past the use of telegraphy in nearly all other communications, and a code test is no longer part of most national licensing exams for amateur radio. Many amateur radio operators continue to make use of the mode, particularly on the shortwave bands and for experimental work such as earth-moon-earth communication, with its inherent signal-to-noise ratio advantages. Morse, using internationally agreed code groups, also allows communications between amateurs who speak different languages. It is also popular with homebrewers as CW-only transmitters are simpler to construct. A similar "legacy" mode popular with home constructors is amplitude modulation (AM), pursued by many vintage amateur radio enthusiasts and aficionados of vacuum tube technology.

For many years, demonstrating a proficiency in Morse code was a requirement to obtain amateur licenses for the high frequency bands (frequencies below 30 MHz), but following changes in international regulations in 2003, countries are no longer required to demand proficiency.[8] As an example, the United States Federal Communications Commission phased out this requirement for all license classes on February 23, 2007.[9][10]

Modern personal computers have encouraged the use of digital modes such as radioteletype (RTTY), which previously required cumbersome mechanical equipment.[11] Hams led the development of packet radio, which has employed protocols such as TCP/IP since the 1970s. Specialized digital modes such as PSK31 allow real-time, low-power communications on the shortwave bands. Echolink using Voice over IP technology has enabled amateurs to communicate through local Internet-connected repeaters and radio nodes[12], while IRLP has allowed the linking of repeaters to provide greater coverage area. Automatic link establishment (ALE) has enabled continuous amateur radio networks to operate on the high frequency bands with global coverage. Other modes, such as FSK441 using software such as WSJT, are used for weak signal modes including meteor scatter and moonbounce communications.

Fast scan amateur television has gained popularity as hobbyists adapt inexpensive consumer video electronics like camcorders and video cards in home computers. Because of the wide bandwidth and stable signals required, amateur television is typically found in the 70 cm (420 MHz–450 MHz) frequency range, though there is also limited use on 33 cm (902 MHz–928 MHz), 23 cm (1240 MHz–1300 MHz) and higher. These requirements also effectively limit the signal range to between 20 and 60 miles (30 km–100 km), however, the use of linked repeater systems can allow transmissions across hundreds of miles.[13]

These repeaters, or automated relay stations, are used on VHF and higher frequencies to increase signal range. Repeaters are usually located on top of a mountain, hill or tall building, and allow operators to communicate over hundreds of square miles using a low power hand-held transceiver. Repeaters can also be linked together by use of other amateur radio bands, landline or the Internet.

Communication satellites called OSCARs (Orbiting Satellite Carrying Amateur Radio) can be accessed, some using a hand-held transceiver (HT) with a stock "rubber duck" antenna. Hams also use the moon, the aurora borealis, and the ionized trails of meteors as reflectors of radio waves.[14] Hams are also often able to make contact with the International Space Station (ISS),[15] as many astronauts and cosmonauts are licensed as Amateur Radio Operators.[16]

Amateur radio operators use their amateur radio station to make contacts with individual hams as well as participating in round table discussion groups or "rag chew sessions" on the air. Some join in regularly scheduled on-air meetings with other amateur radio operators, called "Nets" (as in "networks") which are moderated by a station referred to as "Net Control".[17] Nets can allow operators to learn procedures for emergencies, be an informal round table or be topical, covering specific interests shared by a group.

Newcomers
Many people start their involvement in amateur radio by finding a local club. Clubs often provide information about licensing, local operating practices and technical advice. Newcomers also often study independently by purchasing books or other materials, sometimes with the help of a mentor, teacher or friend. Established amateurs who help newcomers are often referred to as "Elmers" within the ham community.[19][20] In addition, many countries have national amateur radio societies which encourage newcomers and work with government communications regulation authorities for the benefit of all radio 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, Radio Amateurs of Canada, the New Zealand Association of Radio Transmitters and South African Radio League. (See Category:Amateur radio organizations)


[edit] Callsigns
Upon licensing, a radio amateur's national government issues a unique callsign to the radio amateur. The holder of a callsign uses it on the air to legally identify the operator or station during any and all radio communication.[21] In certain jurisdictions, an operator may also select a "vanity" callsign although these must also conform to the issuing government's allocation and structure used for Amateur Radio callsigns.[22] Some jurisdictions, such as the U.S., require that a fee be paid to obtain such a vanity callsign; in others, such as the UK, a fee is not required and the vanity callsign may be selected when the license is applied for.

Callsign structure as prescribed by the ITU, consists of three parts which break down as follows, using the callsign ZS1NAT as an example:

ZS – Shows the country from which the callsign originates and may also indicate the license class. (This callsign is licensed in South Africa, and is CEPT Class 1).
1 – Gives the subdivision of the country or territory indicated in the first part (this one refers to the Western Cape).
NAT – The final part is specific to the holder of the license, identifying that person specifically.
Many countries do not follow the ITU convention for the numeral. In the United Kingdom the calls G2xxx, G3xxx, and G6xx may be issued to stations that are geographically right next to each other. In the United States, the numeral indicates the geographical district the holder resided in when the license was issued. Prior to 1978, US hams were required to obtain a new callsign if they moved out of their geographic district.

Also, for smaller entities, a numeral may be part of the country identification. For example, VP2xxx is in the British West Indies (subdivided into VP2Exx Anguilla, VP2Mxx Monserrat, and VP2Vxx British Virgin Islands), VP5xxx is in the Turks and Caicos Islands, VP6xxx is on Pitcairn Island, VP8xxx is in the Falklands, and VP9xxx is in Bermuda.

Anybody can look up who a specific United States callsign belongs to using the FCC's license search database. Information may be available for other jurisdictions on websites such as Callbook.


[edit] Privileges
Unlike all other RF spectrum users, radio amateurs are allowed to build or modify transmitting equipment, and do not need to obtain type-approval for it. Licensed amateurs can also use any frequency in their bands (rather than being allocated fixed frequencies or channels) and can operate medium to high-powered equipment on a wide range of frequencies[23] so long as they meet certain technical parameters including occupied bandwidth, power, and maintenance of spurious emission.

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 allow worldwide communication, the VHF and UHF bands offer excellent regional communication, and the broad microwave bands have enough space, or bandwidth, for television (known as SSTV and FSTV) transmissions and high-speed data networks.

 
The international symbol for amateur radio, included in the logos of many IARU member societies. The diamond holds a circuit diagram featuring components common to every radio: an antenna, inductor and ground.Although allowable power levels are moderate by commercial standards, they are sufficient to enable global communication. Power limits vary from country to country and between license classes within a country. For example, the power limits for the highest available license classes in a few selected countries are: 2.25 kW in Canada, was 2 kW in the former Yugoslavia, 1.5 kW in the United States, 1 kW in Belgium and Switzerland, 750 W in Germany, 500 W in Italy, 400 W in Australia, India and the United Kingdom, and 150 W in Oman. Lower license classes usually have lower power limits; for example, the lowest license class in the UK has a limit of just 10 W. Amateur radio operators are encouraged both by regulations and tradition of respectful use of the spectrum to use as little power as possible to accomplish the communication[24].

When traveling abroad, visiting amateur operators must follow the rules of the country in which they wish to operate. Some countries have reciprocal international operating agreements allowing hams from other countries to operate within their borders with just their home country license. Other host countries require that the visiting ham apply for a formal permit, or even a new host country-issued license, in advance.

Many jurisdictions issue specialty vehicle registration plates to amateur radio operators who provide proof of an amateur radio license.[25][26] The fees for application and renewal are usually less than standard plates.[25][27]


[edit] Band plans and frequency allocations
Main article: Amateur radio frequency allocations
The International Telecommunication Union (ITU) governs the allocation of communications frequencies worldwide, with participation by each nation's 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 ensure the most effective use of spectrum.

In a few cases, a national telecommunication agency may also allow hams to use frequencies outside of the internationally allocated amateur radio bands. In Trinidad and Tobago, hams are allowed to use a repeater which is located on 148.800 MHz. This repeater is used and maintained by the National Emergency Management Agency (NEMA), but may be used by radio amateurs in times of emergency or during normal times to test their capability and conduct emergency drills. This repeater can also be used by non-ham NEMA staff and REACT members. In Australia and New Zealand ham operators are authorized to use one of the UHF TV channels. In the U.S., in cases of emergency, amateur radio operators may use any frequency including those of other radio services such as police and fire communications and the Alaska statewide emergency frequency of 5167.5 kHz.

Similarly, amateurs in the United States may apply to be registered with the Military Affiliate Radio System (MARS). Once approved and trained, these amateurs also operate on US Government Military frequencies to provide contingency communications and morale message traffic support to the military services.


Learn more:

http://en.wikipedia.org/wiki/Amateur_radio




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My son Evan, taken from his family and friends on March 26, 2010 at the age of 15. We love you and miss you Evan. We will see you again soon in heaven. I miss you son. You were the best son a dad could have. I am so proud of you. Save a place for me.
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