Four dual polarization SIS receivers are available at the telescope for the upcoming observing season. They are designated according to the dewar in which they are housed (A, B, C, or D), followed by the center frequency (in GHz) of their tuning range. Their main characteristics are summarized in Tab. . All receivers are linearly polarized with the E-vectors, before rotation in the Martin-Puplett interferometers, either horizontal or vertical in the Nasmyth cabin. Up to four of these eight receivers can be combined for simultaneous observations in the four ways depicted in Tab. . Note that they cannot be combined with HERA nor with the bolometers. Also listed are typical system temperatures which apply to average summer/winter weather (7mm/4mm of water) at the center of the tuning range and at 45 elevation. All receivers are tuned by the operators from the control room. Experience shows that it normally takes not more than 15 min to tune four such receivers.
receiver | polar- | combinations | range | (SSB) | remark | ||||||||||||
ization | AB | CD | AD | BC | GHz | K | dB | GHz | GHz | K | |||||||
A100 | V | 1 | 3 | 80 - 115.5 | 60 - 80 | 1.5 | 0.5 | 120 | 1 | ||||||||
B100 | H | 1 | 4 | 81 - 115.5 | 60 - 80 | 1.5 | 0.5 | 130 | 1 | ||||||||
C150 | V | 2 | 4 | 129 - 183 | 70 - 125 | 15 - 25 | 4.0 | 1.0 | 200 | ||||||||
D150 | H | 2 | 3 | 129 - 183 | 80 - 125 | 8 - 17 | 4.0 | 1.0 | 200 | ||||||||
A230 | V | 1 | 3 | 197 - 266 | 85 - 150 | 12 - 17 | 4.0 | 1.0 | 420 | 2 | |||||||
B230 | H | 1 | 4 | 197 - 266 | 95 - 160 | 12 - 17 | 4.0 | 1.0 | 420 | 2 | |||||||
C270 | V | 2 | 4 | 241 - 281 | 125 - 250 | 10 - 20 | 4.0 | 1.0 | 900 | 3 | |||||||
D270 | H | 2 | 3 | 241 - 281 | 150 - 250 | 9 - 13 | 4.0 | 1.0 | 900 | 3 | |||||||
HERA | H/V | 210 - 276 | 110 - 380 | 4.0 | 1.0 | 400 | 2, 4 |
According to current planning IRAM will replace the present set of single pixel heterodyne receivers by a new generation receiver designated EMIR (Eight MIxer Receiver). EMIR is expected to be installed during the second half of the winter semester. Because this time scale is still somewhat uncertain and the EMIR characteristics are not yet precisely known, we request observers to still use the characteristics of the present receivers for their proposals. Observations scheduled after the installation of EMIR may get their time allocation adjusted accordingly.