via HACKADAY: A Practical Guide To Understanding How Radios Work

How may radios do you own? Forget the AM/FM, GMRS/FRS radios you listen to or communicate with. We’re talking about the multiple radios and antennae in your phone, your TV, your car, your garage door opener, every computing device you own- you get the idea. It’s doubtful that you can accurately count them even in your own home. But what principles of the electromagnetic spectrum allow radio to work, and how do antenna design, modulation, and mixing affect it? [Michał Zalewski] aka [lcamtuf] aims to inform you with his excellent article Radios, how do they work?

For those of you with a penchant for difficult maths, there’s some good old formulae published in the article that’ll help you understand the physics of radio. For the rest of us, there are a plethora of fantastic illustrations showing some of the less obvious principals, such as why a longer dipole is more directional than a shorter dipole.