Two-way radios provide an inexpensive and powerful method of receiving radio waves through any part of the world. Also known as high frequency , radio is transmitted directly over the AM band in the radio spectrum. Radio waves of this frequency are reflected back to Earth from the ionosphere, and is not absorbed, allowing the signal to travel thousands of kilometres.
Originally developed for military transfer emergency radio is currently used by governments, private organizations and fans to reach large groups of people around the world. Since they are traveling at such large distances, communication krótkofalowa not always as clear as local FM station. Weather conditions can even cause attenuation and signal attenuation, as well as the likelihood of interference from stations on adjacent frequencies.
With all the technology that you have in your home, you may wonder whether listening to the radio krótkofalowego worth the hassle, but part of the allure is the ability to explore stations from other countries and discovery of the unknown. Part of the spectrum of short waves, even for Amateurs who want to communicate back and forth in two-way communication.
The practical advantage krótkofalowego radio is that it is the only way for direct communication from one country to another without an intermediary, such as television or TV. In the event of a global catastrophe or zombie Apocalypse , you’ll be able to stay in contact with the rest of the planet.
Even if the world is not coming to an end, a shortwave radio is an important part of every emergency kit in preparation. Many models available with solar panels, and even with the manual crank, allowing guaranteed operation in any conditions.
What do you hear in krótkofalowym radio?
Before the advent of the Internet, shortwave radio was the primary way many immigrants who, in connection with their homeland. Gaggles of students enrolled in cordless phones a radio station to listen to their national teams in soccer games and other sporting events. Families will abandon the nightly news on television in favor of transferring from home .
Because of the Internet and the proliferation of dozens of channels of cable television, some governments have closed or cut their sentences short. Despite the fact rozczarowującego development, the range of short waves, still offers a wide range of design choices. There is still a fervent community of fans of phones that listen and create interesting and original content.
In addition to the station, pursued by governments and major religious organizations there are several private stations, international that sell blocks of airtime to different groups to provide a wide range of music programs, entertaining and educational. Segments of the spectrum, they are also locked for use by the Amateur, a sea of communication and other operational functions.
It can be argued that modern communication is killing the students of the talkies, but also facilitates the study of the universe high frequency. There are sites dedicated to the creation of the graphics programming of short waves, and even apps for smartphones that share schedules and provide a constantly changing frequency to help You keep track of your favorite radio stations.
A brief history of krótkofalowego radio
The invention of the shortwave radio is often assigned Laureatowi Nobel Prize and enthusiast radiowemu Guglielmo Marconi . He and his assistant Charles Samuel Franklin began an extensive study in 1923, to determine whether short-wave suitable for long-distance transmission. His work led to the creation of a network of service Beam, which joined the UK to Canada in 1926. The service was expanded in Australia, South Africa and India in 1927.
There is evidence that amatorscy operators radiowi to distribute the first transatlantic signal krótkofalowy. Band of low frequency is considered to be Amateur, the 1.8-2.0 MHz, were recognized as unsuitable for communication over long distances and is intended for Amateur use. It was in this “useless” frequencies, hundreds of North American Amateurs were heard in Europe in 1922. The first two-way communication between fans from North America and the Hawaiian Islands were also recorded in 1922 on the same wavelength.
The presence of the natural frequencies and the newly available vacuum tubes allowed radioamatorom to experiment and considerable achievements in the field of technology use of short waves on a large scale, including the first transatlantic bilateral contact in 1923.
Technology krótkofalowa was so cheap investment that quickly eclipsed the use of transoceanic cables and Telegraph and television. In the late 1920-ies more than half of all cross-border calls used the radio, ending the need for further investments of new transoceanic cables and massive long reach radio stations.