10-meter Band - Propagation Characteristics

Propagation Characteristics

Due to its unique spot in the spectrum, 10 metres can be fascinating, if not occasionally challenging, to work. At peak times of the solar cycle when many sunspots appear on the Sun's surface, 10 metres can be alive with extremely long-distance signals, refracting from the F2 layer in the ionosphere. The 10 metre band is primarily a day-time band. As such, generally speaking, the most effective and efficient propagation of radio waves takes place during daylight hours, local time. During periods of increased sunspot activity, "band openings" may begin well before sunrise and continue into the night.

Long distance opportunities via F2 seem to follow the Sun across the globe. In North America, for instance, F2 might bring Europe and Western Asia in the morning, The Americas during midday, and the Pacific and East Asia in late afternoon and early evening.

Even in times of solar minimum, when F2 is rarely available, 10 metres still has some long distance possibilities. Sporadic E propagation can bring in signals from a hundred to many thousands of miles away. Sporadic E on 10 metres is mainly a seasonal event, with late Spring and early Summer being prime time for the mode. A shorter, less-intense period occurs during mid-Winter, often between Christmas and New Year. Other, off-peak openings may be seen almost anytime. Even during solar minimum, F2 openings often occur on transequatorial paths, for example between Europe and Southern Africa or between Pacific North America and the Eastern Pacific islands.

In tropical latitudes 10 metres is open throughout the sunspot cycle, although propagation is often confined to other areas lying along the equator. For example, a good path from West Africa to the Caribbean exists on 10 metres even at solar minimum.