The 4-millimeter band is a portion of the EHF (microwave) radio spectrum internationally allocated to amateur radio and amateur satellite 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 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.
The International Telecommunication Union allocates 76.0 GHz to 81.0 GHz to amateur radio, amateur satellites, radio astronomy and radiolocation (radar) and space research 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 regions.
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 European 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
- "FCC Online Table of Frequency Allocations" (PDF). 47 C.F.R. Federal Communications Commission. May 7, 2019. Retrieved August 7, 2019.
Blondeel Timmerman, Hans (15 March 2009). "75.5-81.5 GHz". International Amateur Radio Union Region 1 Homepage. International Amateur Radio Union Region 1. Retrieved August 4, 2011.
EU35: The band 75.5-76 GHz is in Europe also allocated to the Amateur and Amateur Satellite services
- "VHF Managers Handbook". 7. International Amateur Radio Union Region 1. January 2015. p. 53. Archived from the original (PDF) on June 17, 2018. Retrieved October 27, 2015.
- "IARU Region 2 Band Plan" (PDF). International Amateur Radio Union Region 2. October 14, 2016. p. 15.
- "Distance Records" (PDF). Amateur Radio Relay League. May 21, 2019. Retrieved August 7, 2019.
- Day, Peter; Qaurmby, John (May 9, 2019). "Microwave Distance Records". UK Microwave Group. Retrieved August 7, 2019.
- "Australian VHF - UHF Records" (PDF). Wireless Institute of Australia. August 1, 2019. Retrieved August 7, 2019.[permanent dead link]
- UK Microwave Group's 75 GHz page
- First 75 GHz VUCC - Mount Greylock Expeditionary Force
- Building a 76 GHz transverter
|Range||Band||ITU Region 1||ITU Region 2||ITU Region 3|
|LF||2200 m||135.7–137.8 kHz|
|MF||630 m||472–479 kHz|
|160 m||1.810–1.850 MHz||1.800–2.000 MHz|
|HF||80 / 75 m||3.500–3.800 MHz||3.500–4.000 MHz||3.500–3.900 MHz|
|60 m||5.3515–5.3665 MHz|
|40 m||7.000–7.200 MHz||7.000–7.300 MHz||7.000–7.200 MHz|
|30 m[w]||10.100–10.150 MHz|
|20 m||14.000–14.350 MHz|
|17 m[w]||18.068–18.168 MHz|
|15 m||21.000–21.450 MHz|
|12 m[w]||24.890–24.990 MHz|
|10 m||28.000–29.700 MHz|
|VHF||6 m||50.000–52.000 MHz
|4 m[x]||70.000–70.500 MHz||N/A|
|2 m||144.000–146.000 MHz||144.000–148.000 MHz|
|1.25 m||N/A||220.000–225.000 MHz||N/A|
|UHF||70 cm||430.000–440.000 MHz||430.000–440.000 MHz|
|33 cm||N/A||902.000–928.000 MHz||N/A|
|23 cm||1.240–1.300 GHz|
|13 cm||2.300–2.450 GHz|
|SHF||9 cm||3.400–3.475 GHz[y]||3.300–3.500 GHz|
|5 cm||5.650–5.850 GHz||5.650–5.925 GHz||5.650–5.850 GHz|
|3 cm||10.000–10.500 GHz|
|1.2 cm||24.000–24.250 GHz|
|EHF||6 mm||47.000–47.200 GHz|
|4 mm[y]||75.500 GHz[x] – 81.500 GHz||76.000–81.500 GHz|
|2.5 mm||122.250–123.000 GHz|
|2 mm||134.000–141.000 GHz|
|1 mm||241.000–250.000 GHz|
|THF||Sub-mm||Some administrations have authorized spectrum for amateur use in this region;|
others have declined to regulate frequencies above 300 GHz, leaving them available by default.
[w] HF allocation created at the 1979 World Administrative Radio Conference. These are commonly called the "WARC bands".
|See also: Radio spectrum, Electromagnetic spectrum|