Amanda Jermyn at masslive.com writes, Fessenden's broadcast from Ocean Bluff-Brant Rock in Massachusetts to ships at sea included him reading the Christmas story from the book of Luke and playing Gounod's "O, Holy Night" on the violin.
It's a strange thought that since radio waves travel at the speed of light, Fessenden's broadcast has since traveled 104 light years in all directions from Earth. An advanced alien civilization 104 light years from here might just be listening to this first broadcast right now.
Aliens about 70 light years from here might be tuning in to Churchill's speeches or Nazi propaganda from World War II. If they figured out that the signals they'd picked up in the radio spectrum could be converted to sound, they could hear us. Being aliens, of course, they'd be unlikely to understand our words, but if they had a telescope powerful enough, they could see us.
What aliens might be able to discover about our civilization would depend on the sophistication of their technology. If they're bacteria or virus-like, forget it!
What could be detected might also depend on how much radiation we're sending into space. Our early radio broadcasts were AM, or amplitude modulation, which emitted much stronger radio waves than the later FM, or frequency modulation system.
Today, we also have satellite radio where the signals are directed towards Earth from satellites, rather than out into space. So we now emit far fewer radio signals into space than we used to, giving any alien civilization out there a narrow window of about 100 years to pick up strong signals, from the time we started broadcasting until today.
Read more here.
Note: Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932) was a naturalized American citizen born in Canada. He was an inventor who performed pioneering experiments in radio, including early—possibly the first--radio transmissions of voice and music. In his later career he received hundreds of patents for devices in fields such as high-powered transmitting, sonar, and television.
Read more about him by clicking here.