This is all exactly right. A reasonable analogy is to think of the antenna as a lightbulb that either changes color quickly or changes brightness quickly to se

This is all exactly right. A reasonable analogy is to think of the antenna as a lightbulb that either changes color quickly or changes brightness quickly to send a signal. If you find yourself bathed in, say, green light, it's pretty easy to look around until you see the green lightbulb. It's very nearly the same here except that radio waves are at a much lower frequency than visible light. If you see a signal at 14.313 MHz, you can swing an antenna around and walk in the strongest direction until you get to the source, modulo reflections and whatnot.