Phased VLA Modes for Semester 2013A

by Gustaaf Van Moorsel last modified Dec 31, 2012 by Jonathan Romney

HSA proposals for observing semester 2013A can request the phased VLA in conjunction with the VLBA, and for processing at the Socorro DiFX correlator.  A comprehensive adjunct to the VLA Observational Status Summary, "VLBI at the VLA", discusses the available phased-VLA capabilities, and provides instructions for their use.  This sub-section of the VLBA Observational Status Summary summarizes only the specific modes available, and their compatibility between the two instruments.

Phased-array data will be limited to two VLA subband pairs, in any combination of polarizations, but with each pair in different IFs (AC and BD).  Channelizations at four different bandwidths will be available, as shown in Table 7.  Bandwidths must be uniform within each station, across the entire VLBI array, and throughout the entire duration of the observation.  At the narrower bandwidths, the two pairs of VLA channels limit the baseline sensitivity to less than can be achieved internally on the VLBA.

Table 7:  Phased-VLA / VLBA Compatibility

Bandwidth Data Rate Data System Sub-bands Data Rate

128 2048 DDC 4 2048
64 1024 DDC 4 1024
32 512 PFB 16 2048
16 256 Legacy 8 512