Ultra high frequency

:This article is about the radio frequency. See also UHF (movie), UHF (music video), and UHF (band)

Characteristics

The transmission of radio waves from one point to another is affected by many variables such as atmospheric moisture, the stream of particles from the sun called solar wind, and time of day.

Related Topics:
Atmospheric - Solar wind

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All radio waves are somewhat absorbed by atmospheric moisture. This reduces, or attenuates, the strength of radio signals over long distances. However, this effect increases according to the frequency: UHF signals are generally more degraded by moisture than lower bands such as VHF.

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As well, the layer of the Earth's atmosphere called the ionosphere is filled with charged particles that can reflect radio waves. This can be helpful in transmitting a radio signal, since the wave bounces from the sky to the ground over and over, convering long distances. However, UHF benefits less from this effect than lower (VHF, etc.) frequencies.

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As the atmosphere warms and cools throughout the day, UHF transmissions may be enhanced by tropospheric ducting.

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