Chapter 2 Radio with Pictures Ancient methods of long-distance communication suffered major limitations Smoke signals and drumbeats had a limited range Letters took weeks or months to travel long distances These delays had dramatic effects on people’s lives For example President Abraham Lincoln delivered the Emancipation Proclamation which freed slaves on January 1 1863 The news did not reach the state of Texas until June 19 1865 a full two and a half years later During that time slaves in Texas continued to live in slavery because they did not know they were free Many technologies have bridged the gap between ancient and modern communications 12
Years before television brought news to the corners of the world telegraphs were used to communicate 13
A woman uses a telegraph to send Morse code Television is a relatively recent and highly important technology that has helped connect cultures New means of long-distance communication appeared in the 1800s The first telegraph message was sent in 1844 The telegraph transmitted electric signals through a wire laid between two stations Messages were sent as a series of dots and dashes called Morse code For the first time ever two people in distant cities could communicate in a matter of seconds 14
The telegraph system quickly expanded By 1866 a telegraph line spanned the Atlantic Ocean connecting the United States and Europe International news could be exchanged immediately This changed many aspects of life It even changed how wars were fought and likely affected who won Journalists reported back to their newspapers quickly so events were covered right away Radio Technology At first the telegraph only worked along wires so it could not transmit information to any city without a connected telegraph station Wireless telegraphs solved this problem beginning in 1891 The wireless telegraph could send coded messages through the air without connecting wires An antenna sent a signal that another antenna picked up Wireless telegraphs sent signals using radio waves Today radio waves are used in many technologies including radio and television broadcasting mobile phones satellites and wireless systems EINSTEIN’S TAKE ON RADIO World-renowned physicist Albert Einstein was asked to explain radio in 1938 and he responded You see wire telegraph is a kind of a very very long cat You pull his tail in New York and his head is meowing in Los Angeles Do you understand this And radio operates exactly the same way you send signals here they receive them there The only difference is that there is no cat 1 15
