Receivers

The IF bandwidth of all heterodyne receivers is 500 MHz, except for 230G2 which, coupled to the 1MHz filter bank, has a 1 GHz bandwidth. The following table lists the present possible receiver combinations:

Receivers 4-rec 3-rec

3mm1 * *

3mm2 *

2mm *

230G1 * *

230G2 *

The present 3mm1 and 230G1 H polarization receivers will be replaced next spring by two new systems located in a single dewar. Due to improvements in mixers, LO injection and optics, we expect significantly better system noise temperatures. As before, The V polarization 3 mm receiver (3mm2) or the V polarization 1.3mm receiver (230G2) will be usable with the new H polarization 3mm1 and 230G1 receivers with a high efficiency (in the latter case, at the request of the observer, a mirror will replace the dichroic mirror located on the V polarization ray path). Four receiver operation (3mm1+3mm2+230G1+230G2) using the dichroic mirror is possible, but will increase the noise temperature of 230G2 by about 30 K.

• 3 mm SIS receivers
• 2 mm Receiver
• 1.3 mm Receivers
• Efficiencies, interferences, error beam
• Polarimeter
• General point about receiver operations