I've read that ionosphere mirrors the short radio waves (25-30 MHz). So 2 questions:
- Why this happens? There is material on the internet, but it's rather complicated for me so far, I've just started to study physics. So I'd appreciate if someone explains this in more or less simple way.
- Why this is true only for a particular diapason: 25-30 MHz and why other waves go through the ionosphere without problems?