In this module you will learn how the lower frequency radio spectrum is affected by the environment. Particular emphasis is on HF transmissions and how knowledge about the sun and ionosphere will help you predict how and why HF transmissions vary with time of day, latitude, season and space weather. You should progress through the module in the order below. There are no online answers to the study questions, but you may contact the instructor if there is something you do not understand. Each page below will have navigation button at the bottom of the page that will allow you to return here (the index) or go to the previous or next page.
Introduction to HF and Lower Frequencies
The Ionosphere and Sun
Choosing the Right Frequency
Summary and Additional Information Sources
Last Update: 12/2/2003