This receiver is much more stable since its mixer has been exchanged in July 1994. Receiver temperatures are between 80 and 120 K (see Fig. 4), the image sideband rejection is between 25 dB and 30 dB.
The high rejection of the USB improves the system temperature and the calibration accuracy, particularly for 115 GHz observations, for which the receiver image sideband sees the bright oxygen 118.75 GHz atmospheric line.
It is important to check your calibration on strong reference sources (see IRAM line catalog and updates). Beware also of possible interference between the `second' 1.3 mm receiver, 230G2, and this receiver when operating at harmonic frequencies (the two receivers receive the same polarization; the interference will be a strong and narrow line).