The 1 millimeter band is a portion of the EHF (microwave) radio spectrum internationally allocated to amateur radio and amateur satellite use. The amateur radio and amateur satellite band is between 241 GHz and 250 GHz. Amateurs operate on a primary basis between 248 GHz and 250 GHz and on a secondary basis in the rest of the band. Also, amateurs must protect the radio astronomy service from harmful interference between 241 GHz and 248 GHz. The ITU's allocations are the same in all three ITU Regions.[1]
Some administrations have authorized spectrum for amateur use in this region; others have declined to regulate frequencies above 300 GHz.
[v] All allocations are subject to variation by country. For simplicity, only common allocations found internationally are listed. See a band's article for specifics.
[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 many individual administrations have commonly adopted this allocation under "Article 4.4".
[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.
