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

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

• A. During peak solar eclipses
• B. At night during summer
• C. From dawn to shortly after sunset during high sunspot activity
• D. At noon year-round

Answer: (C)

The best time for long-distance propagation on the 10 meter band is generally from dawn to shortly after sunset during periods of high sunspot activity. This is due to the ionospheric conditions that are most favorable during these times. During daylight hours, the sun's radiation ionizes the D layer of the ionosphere, which can absorb lower frequency signals. However, as the sun rises, the E and F layers become increasingly ionized, allowing for greater reflection of radio waves, particularly for higher frequencies such as those on the 10 meter band. Peak conditions occur shortly after sunrise when signals can travel much longer distances as the atmosphere transitions from night to day. The same principle applies as the sun sets, as the layers remain ionized for some time, allowing for effective reflection of signals. High sunspot activity correlates with increased solar radiation and more effective ionization of the ionosphere, which enhances the potential for long-distance communications. Thus, this option accurately reflects the conditions that facilitate optimal propagation on the 10 meter band.

The best time for long-distance propagation on the 10 meter band is generally from dawn to shortly after sunset during periods of high sunspot activity. This is due to the ionospheric conditions that are most favorable during these times.

During daylight hours, the sun's radiation ionizes the D layer of the ionosphere, which can absorb lower frequency signals. However, as the sun rises, the E and F layers become increasingly ionized, allowing for greater reflection of radio waves, particularly for higher frequencies such as those on the 10 meter band.

Peak conditions occur shortly after sunrise when signals can travel much longer distances as the atmosphere transitions from night to day. The same principle applies as the sun sets, as the layers remain ionized for some time, allowing for effective reflection of signals.

High sunspot activity correlates with increased solar radiation and more effective ionization of the ionosphere, which enhances the potential for long-distance communications. Thus, this option accurately reflects the conditions that facilitate optimal propagation on the 10 meter band.