Antenna Based Calibration

The three basic steps, RF passband, phase and amplitude calibration can be performed independently using antenna based or baseline based parameters. Switching between the two modes is done using commands

SET RF ANTENNA         or  SET RF BASE
SET PHASE ANTENNA      or  SET PHASE BASE
SET AMPLITUDE ANTENNA  or  SET AMPLITUDE BASE

Both solutions can be stored independently in the .IPB file. Note that one can combine an antenna based phase calibration with a baseline based RF calibration for example.

Antenna based calibration normally provides better results, because it reduces the number of unknown and preserve closure relations. The antenna based calibration has a few minor limitations and a priori unusual features

• Only one group of subbands and one band can be calibrated at once. To calibrate both sidebands, proceed in sequence.
• Data must be plotted per baseline, and fits are displayed per baseline also; these displayed functions are the product of the baseline based fitted functions. Although this may look odd at first view, it is the best way to adjust the antenna based parameters.
• As a side effect, $2\pi$ phase ambiguities can be partially resolved by antenna base calibration, but it still helps to use SET PHASE CONTINUOUS.

Antenna based calibration is the default, and is strongly recommended. Switching to baseline-based calibration should only be performed in very peculiar cases.