Amateur radio or Ham radio is a hobby enjoyed by thousands of people throughout the world. A Ham radio amateur uses radio equipment to communicate with other radio amateurs for recreation, public service and self-training. Amateur radio enthusiasts have made significant contributions to science, industry and engineering. The research done by them has founded new industries, built economies and saved lives.
Amateur radio operators enjoy personal two-way communications with friends, family members or complete strangers; they support the larger public community with emergency and disaster communications. The term "amateur" is not a reflection on the skills of the participants, which have often quite advanced knowledge of electronics and radio theory云南快乐十分遗漏前三; rather, "amateur" indicates that amateur communications are not allowed to be made for commercial or money-making purposes.
Many individuals (inventors, engineers, developers, businessmen) have contributed to the development of radio communications and thus the origins of this invention are multiple and controversial. Thomas Edison applied in 1885 to the U.S. Patent Office for a patent on a wireless telegraphy system which anticipated later developments in the field. Nikola Tesla (1856-1943) was able to detect signals from the transmissions of his New York lab at West Point (50 miles away).
Guglielmo Marconi (1874-1937) did some experiments with the transmission and reception of Morse code based radio signals over a distance of a few kilometers in England (1896). Later he was able to send wireless messages across the English Channel and the first transatlantic transmission in 1902. In the period following Marconi's experiments many people throughout the world began experimenting with radio communications.
The first International Radiotelegraph Conference was held in Washington in 1927. At the conference, the amateur radio bands of 80, 40, 20 and 10 meters were established by treaty and international radio callsign prefixes were devised. In 1961 the first orbital satellite carrying amateur radio named OSCAR was launched. OSCAR was the first of a series of amateur radio satellites created throughout the world. In 1979 three new amateur radio bands (30m, 17m and 12 m) were allocated for ham radio (the WARC bands).
云南快乐十分遗漏前三 in the past, amateur radio operators were required to have a qualification endorsement of morse code proficiency to use frequencies below 30 mhz, but from 2003 morse code is no longer an internationally required qualification for an amateur radio license. the countries are no longer obliged by international treaty to require morse code proficiency.
radio amateurs use a variety of transmission modes to communicate with one another:
most amateur radio operators have an area in their home which is dedicated to their radio and equipment known as the "shack" in ham slang. they enjoy meeting each other in person at events held in various locations. radio contests and round table discussion groups are also very popular activities among amateur radio operators.