Part 1: Advancing Radio Science #

Studying for the Technician and General exams probably introduced you to a set of working rules for radio: a silicon diode drops about 0.7 V, a resonant circuit favors one frequency, an SWR reading shows how well a load matches its feed line, and the ionosphere decides which HF bands are open. Rules like these explain what your radio equipment does, and they are enough to set up a station and operate it well. If some of them don’t ring a bell, the Technician and General HamBooks at hambook.org are a good place to review before going further.

Part 1 looks underneath them. You’ll see why those rules hold, where they stop holding, and how to predict with numbers what a part, circuit, signal, antenna, or path will do. That deeper view also explains results that would otherwise seem backward, such as a larger bypass capacitor doing a worse job at VHF than a smaller one.

The chapters follow a signal outward: from the parts inside a radio, through the antenna, and across the path to another station. Each chapter builds on the ones before it. When an explanation leans on an idea that doesn’t feel solid yet, look back at the earlier chapter, or at the earlier HamBook if the idea comes from the Technician or General material.

The math in these chapters is a tool for comparing designs and predicting results before trying them. We’ll introduce it as it becomes useful and work through it one step at a time, keeping the circuit or signal in view. A calculated value should tell you something about the radio, not just fill a space on the page.