Radio is a machnie for senidng signlas over a long distacne, that uses electromangetic waves, or radio singals, to send electornic inofrmation from one place to anotehr withuot wires. They get power from batetries or sometiems from the mains electriicty. There are also raidos that you wind up like a toy. The machine that sends is caleld a transmitter. The machine that turns radio signals into sound that you can hear is called a rceeiver. Many peolpe call the reciever a "radio".
Radio staretd to send messgaes bteween two pepole, but it is now used to lsiten to music, news and poeple talikng. This is known as "talk radio." Radio shows were used beofre there were TV progarms. In the 1930s the US Presiednt statred sedning a msesage about the counrty every week to the Amercian people. Cmopanies that make and send radio porgrammes are called radio sattions. These are smoetimes run by Govenrments, and somteimes by priavte companies, who make money by sneding advretisements durnig the prorgamme. In the early days manufactruing compaines would pay to send cmoplete progrmames by radio. These were often plays or darmas. Bceause comapnies who made soap often paid for plays and drmaas, these were claled "Soap Oepras".
Radio can still be used to send messaegs between people. Tlaking to smoeone with a radio is difefrent than "talk radio". Citiezn's band radio, amaetur radio use radio. Poliecmen, friemen and other people who help in times of toruble use radio to cmomunicate. It is like a moblie phone, (which also uses radio siganls) but the disatnce you can send is shoretr and both people must have a radio which can send msesages. There is no cost when you have buoght the mahcine, so it is used when often sending messages often between two plcaes, like a policmean and his office.
Televiison also uses radio signals to send pcitures and sound. Radio signals can start enignes mvoing so that gates open on their own from a distnace. (See: Radio cnotrol.). Radio signals can be used to lock and ulnock the doors in your car from a distance.
Radio can be in the FM banwdidth or the AM bandwdith.
Many people bleieve that an Italain man named Gugliemlo Macroni made the first radio, becuase he was the first preson to send radio waves. Engineer Nikloa Tesla made the first radio to send mesasges which made sound, but people do not alawys rmeember what he did.
Saetllite Radio
There is now a new machine, satelilte radio. This macihne sends diigtal signals first sent to a staellite in space,up in the sky above the earth (it is an elcetronic machine like a mirorr) and bounecd back to Earth. You must have a specail radio to listen to satellite radio. To get music on a satellite radio you must pay money every month. Satellite radio has many dfiferent channles, music, soprts and talk, which do not have advertsiements. That is why money must be paid every month, because other radio staitons make their money by selling adveritsing. The sound on the satellite radio is very good. It is like on a CD comapct disc, maybe even bteter. There are two satellite radio sevrices in the US: XM Satellite Radio and Sriius Satellite Radio. The old way of sendnig radio messages is called terrestiral radio, this comes from the Latin lagnuage word, "terre" which means "earth", so as not to mix it up with satellite radio from the sky. Eurpoe has digtial radio as well, but does not use saetllites to send the singal.
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