C.12 Summary for non-VLBA antennas

Following the insertion of the amplitude solutions for the non-VLBA antennas, you can return to follow the standard path for calibration of VLBA data. Although the procedures from here on are identical to the VLBA-only case, the observer may wish to pay attention to several issues.

  1.  Many non-VLBA antennas are more sensitive than a single VLBA antenna, it can be a good idea to use the most sensitive antenna as the reference antenna for fringe-fitting.
  2.  Non-VLBA antennas may have a larger delay offset than VLBA antennas. The user should pay close attention to the fringe fits, and be aware of the possibility that non-VLBA antennas may have larger residual delays and rates than a VLBA antenna.
  3.  Many non-VLBA antennas do not slew as rapidly as the VLBA. The FG table supplied by calibration transfer may not include all the on-line flags, and may not incorporate information about the pointing of non-VLBA antennas, and when they arrive on source. Therefore, some judicious flagging by the user may be necessary. See C.10.2 for a discussion of applying flags produced by the scheduling software SCHED.
  4.  The elevation limit for non-VLBA antennas is generally different and usually higher than the VLBA’s limit (> 2) which may cause sources to rise and set at different antennas at different times. For example, the VLA has an elevation limit of 8, this means that a source will rise later and set earlier at the VLA than it does at Pie Town or Los Alamos.