When is generally the best time for long-distance 10 meter band propagation via the F region?

When is generally the best time for long-distance 10 meter band propagation via the F region?

• A. From dawn to shortly after sunset during high sunspot activity
• B. From shortly after sunset to dawn during high sunspot activity
• C. From dawn to shortly after sunset during low sunspot activity
• D. From shortly after sunset to dawn during low sunspot activity

Answer: (A)

The best time for long-distance 10 meter band propagation via the F region is typically from dawn to shortly after sunset during periods of high sunspot activity. The F region of the ionosphere is responsible for reflecting radio waves and facilitating long-distance communication. During high sunspot activity, the ionosphere is more electron-rich, which enhances propagation conditions on higher HF bands like the 10-meter band. In the morning, around dawn, the rising sun begins to ionize the atmosphere, thereby increasing the density of the electron layer in the F region. This process continues through the day, with conditions often peaking just after midday before gradually declining towards sunset. Hence, the time from dawn until shortly after sunset allows for optimal propagation conditions, allowing for better signal strength and distance coverage, particularly during a solar cycle peak with active sunspot regions. Usage of the band outside of these optimal times, especially during low sunspot activity or at night, typically results in poorer propagation conditions due to reduced ionization levels, less effective layering in the ionosphere, and increased absorption of signals.

The best time for long-distance 10 meter band propagation via the F region is typically from dawn to shortly after sunset during periods of high sunspot activity.

The F region of the ionosphere is responsible for reflecting radio waves and facilitating long-distance communication. During high sunspot activity, the ionosphere is more electron-rich, which enhances propagation conditions on higher HF bands like the 10-meter band.

In the morning, around dawn, the rising sun begins to ionize the atmosphere, thereby increasing the density of the electron layer in the F region. This process continues through the day, with conditions often peaking just after midday before gradually declining towards sunset. Hence, the time from dawn until shortly after sunset allows for optimal propagation conditions, allowing for better signal strength and distance coverage, particularly during a solar cycle peak with active sunspot regions.

Usage of the band outside of these optimal times, especially during low sunspot activity or at night, typically results in poorer propagation conditions due to reduced ionization levels, less effective layering in the ionosphere, and increased absorption of signals.