The 4-millimeter band is a portion of the EHF (

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...

) radio spectrum internationally allocated to

amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communic ...

and

amateur satellite An amateur radio satellite is an artificial satellite built and used by amateur radio operators. It forms part of the Amateur-satellite service. These satellites use amateur radio frequency allocations to facilitate communication between amat ...

use. The band is between 75.5 GHz and 81.5 GHz, with some regional and national variations. Due to the lack of

commercial off the shelf Commercial off-the-shelf or commercially available off-the-shelf (COTS) products are packaged or canned (ready-made) hardware or software, which are adapted aftermarket to the needs of the purchasing organization, rather than the commissioning of ...

radios, amateurs who operate on the 4 mm band must design and construct their own equipment. Amateurs often use the band to experiment with the maximum communication distance they can achieve, and they also use it occasionally for radio

contesting Contesting (also known as '' radiosport'') is a competitive activity pursued by amateur radio operators. In a contest, an amateur radio station, which may be operated by an individual or a team, seeks to contact as many other amateur radio stati ...

. Amateur radio shares the band with

radio astronomy Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming f ...

, vehicular

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

s for

adaptive cruise control Adaptive cruise control (ACC) is an available cruise control Advanced driver-assistance systems, advanced driver-assistance system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead. As ...

, and aircraft FOD detection radars.

Allocation

The

International Telecommunication Union The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...

allocates 76.0 GHz to 81.0 GHz to amateur radio, amateur satellites, radio astronomy and

radiolocation Radiolocation, also known as radiolocating or radiopositioning, is the process of finding the location of something through the use of radio waves. It generally refers to passive uses, particularly radar—as well as detecting buried cables, w ...

(radar) and

space research Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medicine ...

downlinks. Amateurs operate on a primary basis between 77.5 GHz and 78.0 GHz and on a secondary basis in the rest of the band. Also, 81.0 GHz to 81.5 GHz is allocated by ITU footnote 5.561A to the amateur and amateur-satellite services on a secondary basis. The ITU's allocations are the same in all three

ITU region The International Telecommunication Union (ITU), in its International Radio Regulations, divides the world into three ITU regions for the purposes of managing the global radio spectrum. Each region has its own set of frequency allocations, the ma ...

s. Until 2006, 75.5 GHz to 76.0 GHz was also allocated by the ITU to amateurs on a primary basis. In response to this change, CEPT added footnote EU35 to the "European Common Allocation Table", which provides a continued allocation of this segment to

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

an amateurs.

List of notable frequencies

*75,976.200 MHz Preferred narrow band calling frequency in CEPT countries *76,032.200 MHz Narrow band calling frequency in some countries *77,500.200 MHz Preferred narrow band calling frequency, outside the CEPT area

Distance records

The current world distance record on the 4 mm band was set by US stations AD6IW and KF6KVG / K6GZA on June 14, 2014. The longest distance achieved on 4 mm in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

was between stations G8KQW and G8CUB on November 23, 2013. In

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, the 4 mm distance record was set by stations VK4FB and VK4CSD on July 18, 2019.

References

External links

UK Microwave Group's 75 GHz page

- Mount Greylock Expeditionary Force

Amateur radio bands {{Amateur-radio-stub

Allocation

List of notable frequencies

Distance records

See also

References

External links