2.5-millimeter band

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

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.


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[edit]

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

Distance records[edit]

The current 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.[4]

The 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.[4]

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.[6]

See also[edit]


  1. ^ a b c "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. ^ a b Day, Peter; Qaurmby, John (May 9, 2019). "Microwave Distance Records". UK Microwave Group. Retrieved August 2, 2019.
  5. ^ "Distance Records" (PDF). Amateur Radio Relay League. May 21, 2019. Retrieved August 2, 2019.
  6. ^ "Australian VHF - UHF Records" (PDF). Wireless Institute of Australia. August 1, 2019. Retrieved August 7, 2019.

External links[edit]