Chapter 1: Building Your Electrical Foundation #

Welcome back to electrical principles! You already know voltage, current, and resistance from your Technician studies. Now we’re going to expand that foundation with the AC circuit concepts that make HF radio work.

As a Technician, you worked mostly with DC concepts and simple AC ideas. Moving forward, HF operation requires understanding how alternating current behaves in more complex ways. We will learn about reactance, the opposition to AC that changes with frequency, and how that contributes to impedance, the combination of resistance and reactance that determines how well your antenna system works. You’ll also explore resonance—the principle behind everything from antenna tuners to crystal filters. We will discuss transformers and how they let us match different impedances, power measurements that help you understand PEP and duty cycles, and the decibel system that hams use to describe signal strength and power ratios.

These aren’t just abstract concepts. Understanding series and parallel circuits helps you design or even just understand antenna matching networks. Learning about reactance will help you understand why your antenna’s SWR changes with frequency. Knowing about transformers reveals how baluns work their magic.

Don’t worry if terms like “inductive reactance” or “impedance transformation” sound intimidating. We’ll break everything down step by step, using practical radio examples throughout. By the end of this chapter, you’ll have the electrical foundation that any General class operator should possess.

Let’s build on what you already know and expand your electrical toolkit!