Select the Single continuum option in the Spectral Type section of the Spectral Setup editor pane. You will be presented with a drop-down list of standard continuum frequency setups for each of the available bands. These were chosen so as to maximize the atmospheric transparency and are the recommended values for continuum observations. For science goals requiring full polarization it is mandatory to use these standard frequencies. For single or dual polarization observations it is possible to change the sky frequency within the specified band, but this must be fully justified in the Technical Justification (Step 3.9). Single Continuum observations are specified in the sky reference frame. The corresponding rest frequency is displayed for the source highlighted in the Targets table below (click on a different source to bring up the associated rest frequency), but this is for reference purposes only.
The spectral windows set up by the OT based on the input continuum frequency for each baseband can be found in the spectral window tables. The representative frequency (used for the time estimate calculations as well as the antenna beamsize) defaults to the centre of the last spectral window. You should verify that this is an appropriate choice and if not (e.g. if it falls in an area of low atmospheric transmission) modify it. You can change the spectral window of the representative frequency using the radio buttons in the spectral window table and change the value of the representative frequency within that spectral window by editing the Representative Frequency box below the tables.
In the Spectral tab you can graphically visualise the spectral configuration (see Fig. 3.3). The proposed sidebands are shaded in yellow, while the frequency ranges and the central frequencies of the spectral windows are respectively indicated by the horizontal and the vertical blue lines labelled Continuum. Since the continuum setting is designed to maximise the spectral bandwidth covered, the spectral windows completely cover the width of the sidebands. Note that the continuum frequency specified actually corresponds to the LO frequency and is not itself observed in Bands 3, 4, 6, 7 and 8. In Band 9, the continuum frequency specified corresponds to the frequency at the centre of the 8 GHz wide upper sideband.