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 on a primary basis. The amateur radio and amateur satellite band is between 47.0 GHz and 47.2 GHz, and the allocation is the same in all three ITU regions.
List of notable frequencies
References
6-millimeter band Wikipedia(Text) CC BY-SA