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Building Wireless Sensor Networks by Robert Faludi

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Radio Basics

What exactly is this thing called radio? In any dictionary or encyclopedia, you’ll find a definition that describes the transmission of information via modulation of waves in the electromagnetic spectrum. Whoa, that’s pretty mysterious, especially when coupled with the mathematics and equations that describe the behavior of radio. These certainly help us work with the medium, yet they still may not answer the question of what it is. If you feel unsatisfied by the words or the math, that’s OK. One helpful way to think of radio is as a well-described mystery. After all, we can’t see radio. We can’t touch radio or hear it or smell it or feel it. Billions of years of evolution haven’t provided us with any direct sensory apparatus for perceiving the radio part of the electromagnetic spectrum at all. Our language around the phenomenon reveals this. The word radio comes from radius, the Latin for a ray or spoke in a wheel, something that propagates from a center outward. True, but pretty vague. Around the turn of the last century it was referred to as “ethereal communication” in a nod to the “ether” that was incorrectly thought to pervade outer space. That turned out to be just wrong. Today it’s often referred to as wireless communication, but that’s not what it is. That’s what it isn’t. Radio is also tomato-less, cheese-less, and bread-less, but that does no better to help us understand it. The element of mystery is fundamental to the human experience of radio, and a ...

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