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Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF). VHF radio waves propagate mainly by line-of-sight , so they are blocked by hills and mountains, although due to refraction they can travel somewhat beyond the visual horizon out to about 160 km (100 miles).
Amateur radio frequency allocations vary around the world. Several bands are common for amateurs worldwide, usually in the HF part of the spectrum. Other bands are national or regional allocations only due to differing allocations for other services, especially in the VHF and UHF parts of the radio spectrum.
Frequencies above 30 MHz are referred to as Very High Frequency (VHF) region and those above 300 MHz are called Ultra High Frequency (UHF). The allocated bands for amateurs are many megahertz wide, allowing for high-fidelity audio transmission modes ( FM ) and very fast data transmission modes that are unfeasible for the kilohertz -wide ...
For analog signals in the United States, VHF signals on channels 2 to 6, the low-VHF range, were limited to 100 kW, high-VHF on channels 7 to 13 to 316 kW, and UHF to 5 MW, well over 10 times the power of the low-VHF transmitter power limit. This greatly increased the cost of transmitting in these frequencies, both in electrical cost as well as ...
The IEEE defines the UHF radar band as frequencies between 300 MHz and 1 GHz. [3] Two other IEEE radar bands overlap the ITU UHF band: the L band between 1 and 2 GHz and the S band between 2 and 4 GHz. UHF television antenna on a residence. This type of antenna, called a Yagi–Uda antenna, is widely used at UHF frequencies.
The Pan-American television frequencies are different for terrestrial and cable television systems. Terrestrial television channels are divided into two bands: the VHF band which comprises channels 2 through 13 and occupies frequencies between 54 and 216 MHz, and the UHF band, which comprises channels 14 through 36 and occupies frequencies between 470 and 608 MHz.
Very high frequency: VHF: VHF: 300 MHz – 3 GHz 1 m – 100 mm: Ultra high frequency: UHF: UHF, L, S: 3–30 GHz 100–10 mm: Super high frequency: SHF: S, C, X, Ku, K, Ka: 30–300 GHz 10–1 mm: Extremely high frequency: EHF: Ka, V, W, mm: 300 GHz – 3 THz 1 mm – 0.1 mm: Tremendously high frequency: THF — Radio Spectrum Allocations in ...
In some large metropolitan areas, such as New York, the UHF-T band (between 470 and 512 MHz) is also used due to congestion on the standard VHF or UHF bands. There are also a number of specific frequencies, in both the VHF and UHF spectrums, that are for business use; some of these have color-coded names, such as Red Dot or Blue Star.