This blog is radioactive...

C'mon in... don't be afraid.
I got my first radio in the 1960's it was a transistor unit slightly larger than a pack of cigarettes and ran off a 9 volt battery. It received local signals on the (medium wave) AM band. The frequencies ran from 531 to 1602 kHz

My uncle had a big clunky radio that used vacuum tubes. People in England refer to them as valves... essentially they are metal plates (in a glass envelop) that transfer weak electronic signals into stronger signals by opening and closing the flow of electrons. His radio had different bands that could receive signals from 2.3 to 26.1MHz. This is known as short wave.

The interesting thing about radio transmissions is the radio wave energy travels in straight lines. For a radio station to reach a large audience, the broadcasting antenna must be on a tall tower or the top of a mountain.

The 'line of sight' exception is with short wave signals. Surrounding the earth is a layer of atmosphere called ionosphere that gets charged from the energy of the sun. The layer acts as a reflecting surface the same way a mirror reflects light... the difference is it's curved. Most short wave signals have enough energy to travel a few thousand miles, bounce up to the ionosphere and bounce back down to the other side of the earth. People who are interested in short wave can catch broadcasts from other countries. That's nothing now... but 75 years ago, it was nothing short of magical!

Internet has changed our lives in that radio stations around the world can feed a signal that people can download and listen to audio without the need for a radio. One company who provides links to stations is iHeartRadio platform where you download their app or log on from their website to choose from more than 700 radio stations around the country. Currently, it's a free service that pounds you with advertisements. But, you can be anywhere with internet and listen your favorite broadcast station.

They offer subscription (pay) service that allows you to skip the ads and customize the song lists to suit what your preference rather than live streaming to the broadcast format.