Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communication equipment to communicate with other radio amateurs for public service, recreation and self-training. A participant is called an amateur radio operator, or a ham.
Amateur radio operators enjoy personal 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.
The term "amateur" is not a reflection on the skills of the participants, which are often quite advanced; rather, "amateur" indicates that amateur radio communications are not allowed to be made for commercial or money-making purposes.
Activities and practices
Radio amateurs 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 remains popular, particularly on the shortwave bands and for experimental work such as Moon-bounce, 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 home-brewers as CW-only transmitters are simpler to construct. 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. As an example, the United States Federal Communications Commission phased out this requirement for all license classes on February 23, 2007.
Modern personal computers have led to a boom in digital modes such as radio-teletype, which previously required cumbersome mechanical equipment. Hams led the development of packet radio, which has even used protocols such as TCP/IP since the 1970s. This has since been augmented by more specialized modes such as PSK31 to 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, while IRLP has allowed easy linking together of repeaters. Other modes, such as FSK441 using software such as WSJT, are used for weak signal modes including meteor scatter and moon-bounce communications.
Similarly, fast scan amateur television, once considered esoteric, has exploded in popularity thanks to cheap 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 (420â€”450 MHz) frequency range, though there is also limited use on 33 cm (902â€”928 MHz), 23 cm (1240â€”1300 MHz) and higher. These requirements also effectively limit the signal range to between 20 and 60 miles (30â€”100 km), however, the use of linked repeater systems can allow transmissions across hundreds of miles.
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, land-line or the Internet.
Communication satellites called OSCARs (Orbiting Satellite Carrying Amateur Radio) can be accessed, some using a handheld transceiver (HT) with a stock "rubber duck" antenna. Hams also use the moon and the ionized trails of meteors as reflectors of radio waves. Hams are also often able to make contact with the International Space Station (ISS), as many astronauts and cosmonauts are licensed as Amateur Radio Operators.
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" Nets can allow operators to learn procedures for emergencies, be an informal round table or be topical, covering specific interests shared by a group.
In all countries, amateur radio operators are required to pass a licensing exam displaying knowledge and understanding of key concepts. In response, hams are granted operating privileges in larger segments of the radio frequency spectrum using a wide variety of communication techniques with higher power levels permitted. This practice is in contrast to unlicensed personal radio services such as CB radio, Multi-Use Radio Service, or Family Radio Service.
In many countries, amateur licensing is a routine civil administrative matter. Amateurs are required to pass an examination to demonstrate technical knowledge, operating competence and awareness of legal and regulatory requirements in order to avoid interference with other amateurs and other radio services. There are often a series of exams available, each progressively more challenging and granting more privileges in terms of frequency availability, power output, permitted experimentation, and in some countries, distinctive call-signs. Some countries such as Great Britain and Australia have begun requiring a practical training course in addition to the written exams in order to obtain a beginner's license, called a Foundation License.
Amateur radio licensing in the United States serves as an example of the way some countries award different levels of amateur radio licenses based on technical knowledge. Three sequential levels of licensing exams (Technician Class, General Class and Amateur Extra Class) are currently offered, which allow operators who pass them access to larger portions of the Amateur Radio spectrum and more desirable call-signs.
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.
Upon licensing, a radio amateur's national government issues a unique call-sign to the radio amateur. The holder of a call-sign uses it on the air to legally identify the operator or station during any and all radio communication. In certain jurisdictions, an operator may also select a "vanity" call-sign. Some jurisdictions, such as the U.S., require that a fee be paid to obtain such a vanity call-sign; in others, such as the UK, a fee is not required and the vanity call-sign may be selected when the license is applied for.
While many hams simply enjoy talking to friends, others pursue a wide variety of specialized interests.
Hand building home-brew amateur radio gear
Designing new antennas
Communicating via amateur satellites
Severe weather spotting
DX communication to far away countries
Using the Internet Radio Linking Project (IRLP) to connect radio repeaters via the Internet
Tracking vehicles using the Automatic Position Reporting System (APRS), which integrates with the GPS
Engaging in the sport of contesting, earning awards, and collecting QSL cards
Amateur Radio Direction Finding, also known as "Fox hunting"
High Speed Telegraphy
Low-power operation (QRP)
Vintage amateur radios, such as those using vacuum tube technology
Hamfests, club meetings and swap meets
Portable, fixed, mobile and handheld operation
VHF, UHF and microwave operation on amateur radio high bands.