HF Radio Tutorials for Amateur Operators

There is a lot of information out there on the Internet, but what about understanding?

This website provides a free tutorial on HF (high frequency) radio for amateur operators that covers important topics such as radio wave propagation and band characteristics. It also includes useful tips for making contacts and operating effectively in the HF bands. So, let's start.

Radio amateurs use various propagation modes.

Figure 1: Illustration of "LOS," Ground Wave and "Skip" Propagation

The three main propagation modes are:
1. Line-of-sight (LOS) is the direct radio wave transmission known also as space wave propagation.
2. Ground Wave Propagation (surface waves) is a property that allows communication even behind a hill or across the horizon.
3. Skywaves enable communication over extremely long distances, sometimes on the other side of the globe.

How is skywave propagation possible?

Skywaves travel through the Earth's upper atmosphere via multi refractions of the ionosphere.

Figure 2: Ionosphere (Thermosphere) is part Earth's Atmosphere

Sunopots Pictures were published by UCAR - Center for Science Education


Figure 3: Two images of the Sun (February 3, 2002)
by Solar and Heliospheric Observatory (SOHO) satellite🗗
courtesy of European Space Agency and NASA.
See explanations here

A number of variables, such as the time of day, the seasons, and solar activity, have an impact on HF radio propagation. During the day HF radio waves travel longer distances than at night.

In conclusion, HF radio propagation is an important topic for radio amateurs who use HF bands for communication. Successful HF radio communications require an understanding of the various propagation modes and the elements that govern HF radio propagation.