The first operation is to select in the current index the calibrator
observations performed during the time period when calibration is
needed, and to plot the visibilities after having selected the
baselines, side bands and/or subbands needed. This is done via
SET BASELINES , SET BANDS ,
SET SUBBANDS commands. Channel number should be specified as X axis and
Phase and/or amplitude as Y axis, SET MODE SPEC. You should
preferrably use SET PHASE CONTINUOUS, since 
jumps may
occur in the passband shape. Then a calibration curve is determined by
command SOLVE RF_PASSBAND . This
command will fit a polynomial into each measured phase or amplitude,
for each line subband. For the line subbands the polynomial is by
default of degree 0 for amplitude and 1 for phase data. Higher
degrees may be specified as arguments to the
SOLVE RF_PASSBAND
command. For the continuum, the ten values are simply stored and will
be used as calibration data.
With option /PLOT, the curve will be plotted with the data points. The calibration curve is then in memory. These PLOT and SOLVE operations will have to be done in several steps, if many subbands are used. The curve for each subband and sideband is kept in memory, so that a single STORE command is needed.