The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, excluding applications in telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in ISM bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation in these bands.
The early history of radio is the history of technology that produces and uses radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio. Radio development began as "wireless telegraphy". Later radio history increasingly involves matters of broadcasting.
Wireless telegraphy or radiotelegraphy is transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term wireless telegraphy was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in Morse code. In a manual system, the sending operator taps on a switch called a telegraph key which turns the transmitter on and off, producing the pulses of radio waves. At the receiver the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code.
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves.
Frequency allocation is the part of spectrum management dealing with the designation and regulation of the electromagnetic spectrum into frequency bands, normally done by governments in most countries. Because radio propagation does not stop at national boundaries, governments have sought to harmonise the allocation of RF bands and their standardization.
The Commission for Communications Regulation (ComReg) is the general communications regulator for Ireland, covering almost all possible types of communications.
A spark-gap transmitter is an obsolete type of radio transmitter which generates radio waves by means of an electric spark. Spark-gap transmitters were the first type of radio transmitter, and were the main type used during the wireless telegraphy or "spark" era, the first three decades of radio, from 1887 to the end of World War I. German physicist Heinrich Hertz built the first experimental spark-gap transmitters in 1887, with which he proved the existence of radio waves and studied their properties.
Amateur radio international reciprocal operating agreements permit amateur radio operators (hams) from one country to operate a station whilst traveling in another without the need to obtain additional licenses or permits.
Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit. The term radio spectrum typically refers to the full frequency range from 1 Hz to 3000 GHz that may be used for wireless communication. Increasing demand for services such as mobile telephones and many others has required changes in the philosophy of spectrum management. Demand for wireless broadband has soared due to technological innovation, such as 3G and 4G mobile services, and the rapid expansion of wireless internet services.
The South African Radio League (SARL), formerly known as the South African Radio Relay League (SARRL), is a non-profit organisation representing the interests of amateur radio enthusiasts in South Africa. The SARL advocates on behalf of its membership and all licensed amateur radio operators in South Africa as the representative of amateur radio to the South African government. This has included the promotion of deregulation and simplification of the amateur radio service, and expansion of the number of amateur radio operators in Southern Africa. The SARL publicises and promotes the role of amateur radio in society, and promotes the use of amateur radio in schools as an entry point into the fields of science and technology. The SARL publishes a magazine called Radio ZS twelve times a year. SARL is the national Member Society representing South Africa in the International Amateur Radio Union and is a Member Society in IARU Region 1.
The 2200-meter or 136 kHz band is the lowest frequency band in which amateur radio operators are licensed to transmit. It was formally allocated to amateurs at the 2007 World Radiocommunication Conference (WRC-07). The band is available on a secondary basis in all ITU regions with the limitation that amateur stations have maximum radiated power of 1 watt effective isotropic radiated power.
The general radiotelephone operator license (GROL) is a license granted by the U.S. Federal Communications Commission (FCC) that is required to operate certain radio equipment. It is required for any person who adjusts, maintains, or internally repairs FCC licensed radiotelephone transmitters in the aviation, maritime, and international fixed public radio services. It is also required to operate any compulsorily equipped ship radiotelephone station with more than 1,500 watts of peak envelope power, a voluntarily equipped ship, or an aeronautical station with more than 1,000 watts of peak envelope power. The GROL is not required for engineering jobs in radio and television broadcasting. It is obtained by taking a test demonstrating an adequate knowledge of the technical and legal aspects of safe radio operation.
The history of amateur radio, dates from the dawn of radio communications, with published instructions for building simple wireless sets appearing at the beginning of the twentieth century. 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, built economies, empowered nations, and saved lives in times of emergency.
Amateur radio or ham radio is practised by more than 22,000 licensed users in India. The first amateur radio operator was licensed in 1921, and by the mid-1930s, there were around 20 amateur radio operators in India. Amateur radio operators played an important part in the Indian independence movement with the establishment of illegal pro-independence radio stations in the 1940s. The three decades after India's independence saw only slow growth in the number of operators until the then Prime Minister of India and amateur radio operator, Rajiv Gandhi (VU2RG), waived the import duty on wireless equipment in 1984. Since then, numbers have picked up, and as of 2007, there were more than 16,000 operators in the country. Amateur radio operators have played a vital role during disasters and national emergencies such as earthquakes, tsunamis, cyclones, floods, and bomb blasts, by providing voluntary emergency communications in the affected areas.
The 1978 regulations established five categories of Amateur radio licence in India. The regulations were revised in 2009 and now only two categories are issued.
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communications. The term "amateur" is used to specify "a duly authorized person interested in radioelectric practice with a purely personal aim and without pecuniary interest"; and to differentiate it from commercial broadcasting, public safety, or professional two-way radio services.
Call signs in Europe are not formally used for broadcast stations.
Call signs in United Kingdom include a three letter country code, and a series of letters and numbers.
The 8 meter band (40 MHz) is at present the lowest portion of the very high frequency (VHF) radio spectrum allocated to amateur radio use. The term refers to the average signal wavelength of 8 meters.
