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** PREPUBLICATION COPY – WORDING SUBJECT TO CHANGE ** Agenda Item 1.7: 1660 MHz Agenda Item 1.7 to consider the results of ITU R studies in accordance with Resolution 222 (Rev.WRC 07) in order to ensure long‐term spectrum availability and access to spectrum necessary to meet requirements for the aeronautical mobile‐satellite (R) service, and to take appropriate action on this subject, while retaining unchanged the generic allocation to the mobile‐satellite service in the bands 1,525‐1,559 MHz and 1,626.5‐1,660.5 MHz; The primary concern for Radio Astronomy is the passive band from 1660 to 1670 MHz, which is shared with other services and is used to investigate phenomena associated with the formation of stars marked by maser emission from the hydroxyl radical (OH) in the stars’ atmosphere. Signals from OH "megamasers" seen in some galaxies are also observed in this band and provide information on the magnetic fields in these galaxies as well as their evolution over cosmic time. Recommendation: Aeronautical mobile‐satellite (R) service transmissions in the overlapping and adjacent bands should have out‐of band emissions below ‐237 dBW/(m2Hz) at registered RAS sites, in accordance with Recommendation ITU‐R RA.769 for spectroscopic observations. 16