Early on, I was playing with a simple AM radio circuit, and had modified the tuning coil. I stumbled onto a very strong signal. The announcer was speaking French, but a few minutes later, the station switched to English. It identified as Radio Canada International.
The tuning circuit was apparently no longer in the AM broadcast band and well into the Shortwave band. Shortwave radio uses a group of frequencies that tend to travel over long distances. They were commonly used to broadcast government sponsored content globally. I wanted to hear more. I was able to find a few strong signals, but my little AM radio gone wrong wasn’t really up to the task. My parents generously indulged me and purchased a multi-band radio from Radio Shack, the Patrolman-9. It included two shortwave “bands”, 4-12 Mhz, and 12-22 Mhz, as well as fire, police, aircraft, and more.
Back in the 1970s, Shortwave Radio was alive and well. There were many stations to be heard, and when they identified, they often played a short musical score, referred to as an interval signal. You learned to listen for the familiar sounds when trying to locate a broadcast at the top or middle of the hour. After the interval signals, or sometimes as part of them, the stations would announce the station identification and location. Here are a few examples:
Radio Canada International (a few notes from “Oh, Canada”)
Radio Deutsche Welle (West Germany, before the reunification, “Es sucht der Bruder seine Brüder” by Beethoven)
Radio Netherlands (“Merck toch hoe sterck”, from a Dutch war song)
Radio Moscow (“Wide is My Motherland”)
Given the time in history when these stations were active, broadcasting your message to the entire world was, motivated by, if not directly stated, political dogma. This was certainly true of the United States which ran the Voice of America (VOA) and the Soviet Union (USSR) which among others, ran Radio Moscow.