AM broadcasting is emission of sound, sometimes with associated metadata, by radio signals intended for a wide audience to receive it. In conventional terrestrial radio broadcasting, the radio stations broadcast their radio waves from a terrestrial station to an area where their signal can be received. The advantage of this type of radio service is that it is easily detectable from a long distance, as it reaches many more people at a lower frequency than a conventional station. But it has another huge drawback as well.
In the Second World War, the Germans were able to jam the British Radio Service, which was transmitting vital news from London to Africa and the Middle East. To overcome this problem, the Americans developed their own radio system to spread news throughout the world. Their first broadcasts were received in Russia and they helped the Americans win the world war. Similarly, to overcome the obstacles, the Russians developed their own systems, and today we have modern radios that are able to send radio signals all around the world.