The 15 GHz band is one of the most important bands used by the RAS for continuum observations, which define the frequency variation of radiation in sufficient detail to enable conclusions to be reached concerning the physical mechanisms responsible for such emissions. This band is also important for monitoring the intensity variability of quasars. These tremendously distant and enigmatic objects have been found to emit energy that varies in intensity in periods of weeks or months. The energy emitted during any one burst from a quasar is equivalent to converting the mass of a few hundred million stars to energy, yet we do not understand the fundamental physics that can produce such events. Similarly, the 6.7 GHz band is important for spectral line observations of methanol.
Methanol is a basic organic compound, which plays a role in biogenesis.
Since the only other observable emission from methanol would be in the heavily occupied spectrum near 12.178 GHz, observations at 6.7 GHz provide the last remaining portal to quantify the abundance and distribution of methanol on a galactic scale. The interference threshold limits to be used for coordination purposes are given in Recommendation ITU-R RA.769, which are based, inter alia, on the assumption of an antenna gain of 0 dBi toward the interfering transmitter. Appendix B attached hereto contains calculations recently performed to investigate the impact of satellite downlink transmissions on RAS observations in the 15.35-15.40 GHz band. In light of the strong likelihood that the 15 GHz allocation will be modified, CORF asserts that it would not be in the interest of any parties, including that of the Commission and satellite operators, to go through the expense and burden of allocating this band, only to have to revise the allocation in such a short period of time. As the Commission knows, the 6.650-6.670 GHz band is included under Footnote S5.149, which urges administrations to take all practicable steps to protect RAS observations from harmful interference.