Wireless Internet Service Providers - or WISPs - use radio technology extensively, so a thorough understanding of radio concepts is a fundamental starting point for anyone who wants to operate a WISP. The good news is that there are a great many freely available tools to help with this, and the basics aren’t too difficult to understand. While there will always be an element of trial-and-error (mathematical models can only come so close to mirroring reality), a solid understanding of the basics can significantly shorten the time to deployment of a wireless link – and reduce costly errors in putting up connections that do not work to their full potential.
After establishing a few wireless links, and with some reading, the new WISP-operator will quickly start to develop solid instincts regarding what will, and what won’t, work in the real world. Combined with the reference charts and procedures outlined in this book, you should be able to start building useful wireless links with a high-degree of confidence.
This section starts with an overview of how radio works, and an explanation of the fundamental unit of measurement in the radio world: decibels. It then discusses different available frequency bands, wireless protocols and the concept of channel width. Armed with this knowledge, the reader is guided through the task of creating a “link budget” – a summary of all of the major factors that affect a link, and the creation of a worksheet to understand if a link will work at all, and how well it can be expected to work for a given distance. Next, the effects of obstructions on the radio path will be discussed, along with a mathematical model called “Fresnel zones” that can be used to determine the clearance required for a link to function properly. Rain fade, antenna angle/down-tilt and other factors that can affect coverage are then discussed, followed by a series of real-world examples to illustrate the usefulness of this approach.
This section is the most theory-heavy and least practical of the entire book. However, it is highly recommended to bear with it, and plough through. Most of the other radio concepts in this book assume a basic knowledge of these concepts, so it functions as the underpinnings of much of the rest of this title.Up To Contents Chapter 1, How Does Radio Work? »
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