The tuning band of the new 3mm1 (H polarization) receiver will remain 81 - 116 GHz; its receiver temperature will be better than 100 K over the entire band; the image side band rejection is expected to be at least 20 dB. The tuning band of the 3mm2 receiver is 82 - 116 GHz; its receiver temperature is between 70 and 90 K with image side band rejection between 25 and 30dB.
The high rejection of the USB improves the system temperature and the calibration accuracy, particularly for 115 GHz observations, for which the receiver image side band sees the bright oxygen 118.75 GHz atmospheric line.
It is important to check your calibration on strong reference sources (see IRAM line catalogue 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).
We expect to continue to use 3mm1 as the standard pointing receiver.