Radio waves with wavelengths from 1 mm to 10 m

Ultra short waves (VHF, Ultra short waves) are radio waves with wavelengths from 1 mm to 10 m. The frequency range of VHF is therefore from 30 MHz to 300 GHz. Ultra short waves include radio waves from the meter (MV), decimeter (DMV), centimeter (CMV) wave ranges, and millimeter waves
(or very high frequency — VHF, ultra high frequency — UHF, super high frequency — SHF, extremely high frequency — EHF ranges).

Standard Division of the VHF Range

Wave range	Wavelength	Frequency, MHz
Meter (VHF)	10 m – 1 m	30 - 300
Decimeter (UHF)	1 m – 10 cm	300 - 3000
Centimeter (SHF)	10 cm – 1 cm	3000 - 30000
Millimeter (EHF)	1 cm – 1 mm	30000 - 300000

Propagation of Ultra Short Waves

Similar to light waves, ultra short waves propagate in straight lines and only bend around objects whose geometric dimensions are comparable to the wavelength. The bending of obstacles by radio waves (diffraction) becomes more pronounced as the wavelength increases.

VHF-range radio waves propagate practically within the limits of line-of-sight and, without reflecting from the ionosphere, escape into outer space. In VHF radio communication, only the ground wave is used. Large artificial structures and mountains encountered along the radio wave path, as well as the Earth's curvature, impede wave propagation along the surface. Communication range depends on obstacles along the wave path, antenna height above the ground, and transmitter power, but even under the most favorable conditions, the maximum range can be up to 50–70 km.

Applications of VHF

The use of VHF ranges is explained by advantages inherent to radio waves of this range compared with waves of other ranges. VHF-range radio waves reflect well from objects along their path. This range experiences significantly fewer industrial interferences.

VHF is widely used in communication and broadcasting systems. Most such systems operate within areas limited by line-of-sight conditions. Increasing communication range is achieved in microwave relay lines (MRL) — chains of relay stations spaced within direct visibility of each other. MRLs use UHF- and SHF-range waves. The use of an artificial Earth satellite as a relay in MRL ensures communication between ground points more than 10,000 km apart.

The VHF range is the only one in which television broadcasts are carried out and high-quality frequency-modulated (FM) radio broadcasting is organized.

VHF is also used in radar systems, short-range and radio astronomical navigation, radio remote control, and radio distance measurement. VHF-range radio waves are employed in studying the atmospheres of stars, planets, and nebulae (radio astronomy), in medicine for measuring the temperature of biological objects (radiothermography), and in studying the structure and composition of matter (radio spectrometry).