WHAT'S INSIDE: PERSONAL AUDIO
- MP3 Players
The air around you is bursting with radio waves -- and you can tap into them with minimal effort. With a simple radio scanner, all sorts of transmissions are within your earshot. Find out how radio scanners let you listen in on everything from police to astronaut transmissions.
Have you ever noticed a difference in the quality of radio signals depending on the time of day? Why do you hear some radio stations better at night than in the day?