Amateur radio

Amateur radio
Name	Amateur radio
Country	Worldwide

Amateur radio, also known as ham radio, is a licensed radio service for non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication. Operators, often called hams, use designated radio frequency spectra to communicate across cities, countries, and even into space. The hobby encompasses a wide range of activities, from casual conversation to technical research, and is governed by international agreements and national regulations.

Overview

The service is defined by its purpose of personal wireless experimentation and its role in providing a pool of trained radio operators and technicians. Practitioners communicate using various modes including Morse code, voice, and digital data transmissions. A foundational principle is its contribution to the public good, particularly in providing critical communications support during disasters when other systems fail, as seen in events like Hurricane Katrina and the 2011 Tōhoku earthquake and tsunami. Organizations such as the American Radio Relay League and the Radio Society of Great Britain represent the interests of enthusiasts and promote the hobby.

Licensing and regulation

Operating privileges are granted by national regulatory authorities following the successful completion of examinations. In the United States, the Federal Communications Commission administers licensing, while in the United Kingdom, it is handled by Ofcom. The International Telecommunication Union, through its Radio Regulations, allocates frequency bands for the service worldwide. License classes, such as the Amateur Extra or Foundation Licence, determine the frequency ranges and power levels an operator may use. These exams typically cover radio theory, regulations, and operating practices to ensure efficient and interference-free use of the spectrum.

Activities and practices

Enthusiasts engage in a diverse array of pursuits. DXing involves making long-distance contacts with distant stations, often pursued for awards from entities like the ARRL DX Century Club. Contesting is a competitive activity where operators aim to contact as many stations as possible within a set period. Many participate in emergency communications networks, such as the Amateur Radio Emergency Service. Other popular activities include building homebrew equipment, communicating via amateur radio satellites like those in the AMSAT program, and experimenting with low-power QRP operation.

Technology and equipment

A basic station typically consists of a transceiver, a power supply, and an antenna. Operators may use simple wire antennas or complex directional arrays like Yagi or log-periodic designs. Modes of communication have evolved from traditional amplitude modulation and single-sideband modulation to sophisticated digital protocols such as FT8 and APRS. Advances in technology have integrated software-defined radios and computer control, allowing for new forms of experimentation. Pioneering work by individuals like Edwin Armstrong and institutions like the Massachusetts Institute of Technology has historically influenced the technology used.

History

The origins trace back to the late 19th and early 20th centuries with pioneers like Guglielmo Marconi and Nikola Tesla. Early experimenters, often using spark-gap transmitters, were instrumental in advancing wireless technology. The sinking of the RMS Titanic highlighted the critical role of wireless operators. The first formal licensing began after the passage of the Radio Act of 1912 in the United States. The hobby grew significantly after World War II, with surplus military equipment becoming available. Key historical figures include Hiram Percy Maxim, founder of the American Radio Relay League, and Clinton B. DeSoto, who documented its early culture.

International aspects

It is a global hobby facilitated by the International Telecommunication Union and its World Radiocommunication Conference. The International Amateur Radio Union is the worldwide federation of national societies that represents the service at the ITU. Reciprocal operating agreements, such as those outlined in the CEPT recommendation, allow licensed operators to operate in many countries. Major international events include the World Radiosport Team Championship and the annual Field Day exercise. Communication often bridges political and cultural divides, with contacts between nations like the United States and the Soviet Union having been notable during the Cold War.

Category:Radio communications Category:Hobbies Category:Amateur radio