Which statement is true about Low Frequency and Medium Frequency surface waves?

Which statement is true about Low Frequency and Medium Frequency surface waves?

• A. They travel along the Earth's contour
• B. They travel by line-of-sight
• C. They reflect off the ionosphere
• D. They travel into space

Answer: (A)

Low and medium frequency surface waves propagate mainly as groundwave, traveling along the Earth's surface and following its contour. This happens because the wave interacts with the boundary between air and ground, letting energy stay near the surface and bend around terrain. As a result, these signals can reach well beyond the horizon, especially over conductive ground like seawater or moist soil. The reach is greater at the lower end of the band and with more conductive terrain. They are not limited to line-of-sight, and they do not rely on ionospheric reflection (that’s a feature of higher-frequency skywaves). They also do not travel into space. So traveling along the Earth's contour best describes LF/MF surface-wave behavior.

Low and medium frequency surface waves propagate mainly as groundwave, traveling along the Earth's surface and following its contour. This happens because the wave interacts with the boundary between air and ground, letting energy stay near the surface and bend around terrain. As a result, these signals can reach well beyond the horizon, especially over conductive ground like seawater or moist soil. The reach is greater at the lower end of the band and with more conductive terrain. They are not limited to line-of-sight, and they do not rely on ionospheric reflection (that’s a feature of higher-frequency skywaves). They also do not travel into space. So traveling along the Earth's contour best describes LF/MF surface-wave behavior.