2.5-millimeter band

The 2.5-millimeter or 122 GHz band is a portion of the EHF (microwave) radio spectrum internationally allocated to amateur radio use between 122.250 GHz and 123.000 GHz.[1]

The band is close to a molecular resonance of oxygen at 120 GHz, which causes significant atmospheric propagation losses, similar to that found at 60 GHz.

Due to the lack of commercial off the shelf radios, amateurs who operate on the 2.5 mm band must design and construct their own equipment, and those who do, often attempt to set communication distance records for the band.

Allocation

The International Telecommunication Union allocates 122.250 GHz and 123.000 GHz to amateur radio on a secondary basis. As secondary users, amateurs must protect the fixed, mobile and inter-satellite services from harmful interference, which share the band with amateurs. In addition, 122 GHz to 123 GHz is an ISM band, and all users must accept interference caused by ISM devices. Amateur satellite operations are not permitted, and the ITU's allocations are the same in all three ITU Regions.[1]

List of notable frequencies
  • 122.250 to 122.251 GHz Narrow band modes[2][3]
  • 122.5 GHz ISM band center frequency[1]

Distance records

The current world distance record on the 2.5 mm band is 139 kilometres (86 mi) set by stations K6ML, KB6BA and N9JIM on February 17, 2020. [4] [5]

The previous world distance record on the 2.5 mm band was 132 kilometres (82 mi) set by Austrian stations OE5VRL and OE3WOG on October 19, 2013.[6]

The previous United States distance record was 114 kilometres (71 mi) set by stations WA1ZMS and W4WWQ on January 18, 2005.[5]

The longest distance achieved on 2.5 mm in the United Kingdom was 35.8 kilometres (22.2 mi) between stations DB6NT and DG8EB on August 6, 2017.[6]

In Australia, the 2.5 mm distance record was 59.6 kilometres (37.0 mi) set by stations VK3CV and VK3NH on June 24, 2019.[7]

See also

References
  1. "FCC Online Table of Frequency Allocations" (PDF). 47 C.F.R. Federal Communications Commission. May 7, 2019. Retrieved August 7, 2019.
  2. "VHF Managers Handbook" (PDF). 7. International Amateur Radio Union Region 1. January 2015. p. 54. Retrieved October 27, 2015.
  3. "IARU Region 2 Band Plan" (PDF). International Amateur Radio Union Region 2. October 14, 2016. p. 16.
  4. http://www.arrl.org/news/new-world-distance-record-claimed-on-122-ghz
  5. "Distance Records" (PDF). Amateur Radio Relay League. April 5, 2020. Retrieved September 6, 2020.
  6. Day, Peter; Quarmby, John (May 9, 2019). "Microwave Distance Records". UK Microwave Group. Retrieved August 2, 2019.
  7. "Australian VHF - UHF Records" (PDF). Wireless Institute of Australia. August 1, 2019. Retrieved August 7, 2019.
International amateur radio frequency allocations
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
(50.000–54.000 MHz)[y]		 50.000–54.000 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
(420.000–450.000 MHz)[y]
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".
[x] This is not mentioned in the ITU's Table of Frequency Allocations, but individual administrations may make allocations under "Article 4.4". ITU Radio Regulations.. See the appropriate Wiki page for further information.
[y] This includes a currently active footnote allocation mentioned in the ITU's Table of Frequency Allocations. These allocations may only apply to a group of countries.

See also: Radio spectrum, Electromagnetic spectrum
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