The 3 mm and 1.3 mm receivers of all antennas have now been re-aligned
to within , thereby removing the pending limitations on dual-frequency
observations. Surface adjustments and optimization of the
subreflector position have also been performed to improve the overall
efficiency.
The subreflector of antenna 3 has been exchanged with that foreseen for Antenna 5, and is currently being resurfaced by MAN.
Thorough investigations have improved the 1.3mm total power
stability: a level of 2-3 is now reached.
This allows phase compensation
to about 20 degrees rms at 230 GHz under clear sky conditions.