Keywords: astro

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## Receiver setup

The receiver tuning is selected by the `LINE` command, which has the same syntax as the corresponding command in the `OBS` software on Plateau de Bure:

`LINE name frequency band lock center harm /RECEIVER_BAND irec`

`name` is a line name, only used to label the plot; `frequency` is the rest frequency in GHz; `band` should be USB or LSB; `lock` is LOW or HIGH [optional, default LOW]; `center` is the IF1 frequency (in MHz) that must correspond to the required rest frequency [optional, default 6500]; `harm` is the harmonic number [optional, reserved for experts]. The `/RECEIVER_BAND` option is optional, the software will automatically find the appropriate receiver band, depending on the rest frequency.

It is highly recommended not to center the line at 6 GHz. This is because the correlator will analyse four 1 GHz-wide slices of the 4 GHz bandwidths, and 6 GHz is very precisely at the limit between two such adjacents quarters (see below).

The `LINE` command produces a plot of both the LSB and USB frequency coverage (the non-selected band being in light grey). The four quarters that are analyzed by the IF/correlator system are indicated by horizontal arrows (see Fig. ). Vertical lines indicate the positions of the main molecular lines.

Figure: Plateau de Bure frequency coverage: ouptut of `LINE test 100 LSB`. Both the LSB and USB frequency coverages are displaye.

Figure: Plateau de Bure frequency coverage: ouptut of LINE; NARROW; SPECTRAL commands.

Next: Correlator setup Up: Receiver and correlator setup Previous: Receiver and correlator setup Contents