Sorry if its a simple question but I was wondering what EM waves are composed of. Is it like an electron beam travelling through the air and the magnetic field a consequence of the moving electrons? Another thing thats been really confusing me and no matter how many radio circuit tutorials I look at I can't find the answer to this question. How do the EM waves travel? Lets say I broadcast radio waves of a specific frequency from Portugal and I need a radio station in New Zealand to receive my radio waves. The electrons leave the antenna and enter the air. From what I gather they start off in a straight line then spread out as they get further away from the antenna. Where do they go before the antenna in New Zealand receives them? What if I need one radio station in New Zealand and another one in Venezuela? Do these radio signals enter the atmosphere or what? In that case are long distance radio waves scattered all over to every single part of the world?