Observing must be stopped before carrying out the following. It is also
advisable to close the correlator file
CAOBScorr closefile.
You should note that the delay and phase calibration for the Array will be destroyed on those antennas to which the EARLY calibration is applied. This means you will need to run CACAL after you have completed the early/normal calibration.
To take the data, first ensure that the the correlator is set up to report
auto-correlations (FULL_128_2 is the recommended correlator
configuration), then type
CAOBSearly
to set up the correct scan type for taking the data. Then, on a xbones
terminal, start the EARLY program
xbones$early.
The program will display a title message, the correlator products it will use
and then will report that it is waiting for CAOBS to start. You should then
start the Array tracking
CAOBStrack 1.
It doesn't matter what source it is, the early scan pattern will disable the antennas anyway. However, it is important that you choose a frequency that is actually 'on axis' at the time of the calibration. It is normal to do this calibration as a dual frequency operation.