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 summarised in Tab. 1. 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. 1.
Note that they cannot be combined with HERA nor with the bolometers.
Also listed are typical system temperatures which apply to average
summer weather (7mm 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 | polari- | combinations | tuning range | ![]() |
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remark | |||
zation | 1 | 2 | 3 | 4 | GHz | K | dB | GHz | GHz | K | ||
A100 | V | 1 | 3 | 80 - 115.5 | 60 - 80 | ![]() |
1.5 | 0.5 | 120 | |||
B100 | H | 1 | 4 | 81 - 115.5 | 60 - 80 | ![]() |
1.5 | 0.5 | 120 | 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 | 450 | 2 | ||
B230 | H | 1 | 4 | 197 - 266 | 95 - 160 | 12 - 17 | 4.0 | 1.0 | 450 | 2 | ||
C270 | V | 2 | 4 | 241 - 281 | 125 - 250 | 10 - 20 | 4.0 | 1.0 | 1000 | 3 | ||
D270 | H | 2 | 3 | 241 - 281 | 150 - 250 | 9 - 13 | 4.0 | 1.0 | 1000 | 3 | ||
HERA | H/V | 210 - 276 | 110 - 380 | ![]() |
4.0 | 1.0 | 400 | 2, 4 |