6-millimeter band

The 6-millimeter or 47 GHz band is a portion of the EHF (microwave) radio spectrum internationally allocated to amateur radio and amateur satellite use between 47.0 GHz and 47.2 GHz.

Due to the lack of commercial off the shelf radios, amateurs who operate on the 6 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. In some areas, amateurs maintain 47 GHz propagation beacons on mountain tops. The band has been successfully used by amateurs in moon bounce contacts.

Allocation
The International Telecommunication Union allocates 47.0 GHz to 47.2 GHz to amateur radio and amateur satellites on a primary basis in all three ITU regions.

It is the only EHF band amateurs do not share with other radio services, and it is the only band above 2 meters which is exclusively for the amateur services in its entirety.

List of notable frequencies

 * 47.0882 GHz Narrow band calling frequency
 * 47.088 GHz Propagation beacons

Distance records
The current world distance record on the 6 mm band was 344.8 km set by US stations AD6FP and W6QIW on September 19, 2015.

The longest distance achieved on 6 mm in the United Kingdom was 203 km between stations GM7MRF / GM0HNW and GW0IVA on October 21, 2001.

In Australia, the 6 mm distance record was 181.2 km set by stations VK5KK/3 and VK5ZD/3 on November 14, 2019.

The 6 mm Earth-Moon-Earth record was 9967 km set by stations AD6FP and RW3BP on January 23, 2005.