The HF spectrum (3-30 MHz) is magical. It bounces off the ionosphere, circles the globe, and lets you chat with a retiree in New Zealand while drinking coffee in Ohio. But the antennas required are famously large. A full-wave loop on 40 meters stretches 140 feet. A 3-element Yagi for 20 meters spans over 20 feet on a 40-foot boom.
This book is often recommended over the ARRL Antenna Book for those who want a deeper conceptual understanding of why certain antennas work in specific spots. It is a "must-have" for any radio enthusiast who likes to experiment or build their own gear. hf antennas for all locations moxon pdf
Ensure "Background graphics" is checked in the settings to preserve the visual text diagrams. The HF spectrum (3-30 MHz) is magical