The method described in this section is only meant for VLA data from before February 2013 (before the phased-EVLA came on-line). The observation being calibrated may have incorporated either a single VLA antenna or the phased VLA, but the amplitude calibration parameters for the VLA were not transferred automatically. You will need to obtain an input text file for the VLA then run ANTAB before APCAL. Before February 2013, the gains and system temperatures for this file, in an appropriate format, were supplied in a file called xxxxxcal.y.gz’, where ‘xxxxx’ is the observation code (e.g., ‘bm120’), located at http://www.vlba.nrao.edu/astro/VOBS/astronomy/mmmyy/xxxxx/. That file contains instructions on editing the file to get correct inputs. For a phased array or a 1.3-cm observation in which 3 antennas are used, follow the instructions in §C.11.2; for a single antenna, use §C.11.1.
The method described in this section is only meant for VLA data from before February 2013. Depending on the age of your observation, you may have to add an INDEX entry within the TSYS card (Do not separate the INDEX entry from the TSYS entry by a “/” !!!), un-comment the GAIN line for your particular observing frequency, and un-comment the TSYS line. There are examples of INDEX entries in the comments at the head of the file.
Beginning in June 2003, the INDEX, GAIN, and TSYS information in this table are reformatted to be directly acceptable to . You should check the times in the text file to make sure that your observation has been properly described. Only a few special cases will require editing of the file; in most cases you are able to invoke ANTAB with no editing. Once you are satisfied with the ANTAB file, load the data following the directions in §C.10.1.
The method described in this section is only meant for phased-VLA data from before February 2013. The VLA may be phased on a program source (‘STRONG’), or may be phased on a phase-reference source (‘CAL-PHASE’), with the resulting solutions applied to the program source (‘TARGET’). Rather than recording a system temperature, the VLA system will record a ratio of antenna temperature to system temperature, which will vary as the array phases up. In order to convert the ratio of antenna and system temperatures to a usable gain, the flux density of some source will be needed.