Radio Amateur Quiz Canadian License

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Question A-007-007-011

Which antenna system and operating frequency are most suitable for Near Vertical Incidence (NVIS) communications?

Correct Answer

A horizontal antenna less than 1/4 wavelength above ground and a frequency below the current critical frequency

Explanation

NVIS relies on radiating signals almost straight up to be reflected by the ionosphere. This is best achieved with a horizontal antenna mounted low (typically 0.1 to 0.25 wavelengths above ground) and using frequencies just below the ionosphere's critical frequency for the desired layer.

Warning: Generated by AI