Loading the DAS

  The DAS is started by specifying it as the backend by entering

ICL> BE DAS

at the ICL prompt. The frontend should already have been set. No switching or re-cabling is required; the IF switch will select the appropriate receiver. The Total Power Selector switch should always be set to channel 1 in order to use the CBE for pointing, focussing, etc. For dual-polarisation receivers it may occasionally need to be set to channel 2.

The following will be required if the prompt is switched on (note, it will remember what you typed in last time!):

• Bandwidth. Select one of the options for bandwidth (see section 6), or type File, in which case it will prompt for the name of a non-standard configuration file (section 7).

• Continuous Calibration? Choose yes in most cases, except in the case of raster mapping (see section 4.1 for more details).

• Wideband? Only if RxC2 is the frontend. See section 6.1 for details.

At this point, it will display a message describing the configuration setup and, in the case of non-standard configs, noting what the Frontend frequency and sideband should be. You must read this message.

• Setting IF Levels