Antenna technical data
The 32-m antenna was inaugurated on October 28, 1988.
· Primary mirror dish (D): 32 m (paraboloid) with an active surface system consisting of 244 actuators
· Secondary mirror dish (d): 3.2 m (hyperboloid)
Primary mirror focal length (F1) = 10.259 m
Focal Ratio (F1/D) = 0.33
Cassegrain Focal length (F2) = 97.36 m
Focal Ratio (F2/D) = 3.04
Total Surface Accuracy (RSS): 350÷400 mm (antenna efficiency is quite constant vs. elevation, due to the primary mirror active surface system which compensates for the gravitational deformations).
Aperture Efficiency (theoretical maximum, i.e. not including surface effects ≈ 58%)
· 57% @ 5 GHz (measured);
· 50% @ 22 GHz (measured);
· 40% @ 43 GHz (measured).
On both the azimuth and elevation axes, 0.002 degrees RMS. Thanks to an accurate pointing model, the pointing doesn’t need to be calibrated during standard antenna operations.
It is possible to change the observation configuration of the antenna by switching among receivers, as reported in the following:
· the interchange among them must be scheduled to be done during working hours and it takes about 4 hours;
· between Primary focus receivers to Cassegrain focus receivers (or vice versa) is possiblewithin 4 minutes.
Focal Position F1 (Primary focus)
In the Primary focus position a box is installed, hosting a coaxial, uncooled, S/X-band receiver.
Focal Position F2 (Cassegrain focus)
In the Cassegrain Focus position, four receivers are available:
· Clow-band receiver, mono-feed, cryogenic;
· Chigh-band receiver, mono-feed, not cooled;
· K-band receiver, mono-feed, cryogenic;
· Q-band receiver, mono-feed, cryogenic.