[evlatests] AJ329, C band, August 7

[Jim Ulvestad]

Hi all,

This is a brief report on AJ329, C band, observed August 7.
It's a week old, but I didn't have time to reduce the data until
a plane ride yesterday.  There are a couple possible items
of interest.

Run was C band, default frequencies (4885.1 and 4835.1),
50 MHz bandwidth, standard continuum, 10-sec averaging,
used antennas 13, 14, and 16.  Run was dynamically scheduled.

As for the X band run on August 8, there was a problem
with the first record of each scan being bad only for
the EVLA-EVLA baselines.  In looking carefully at the
LISTR output, I realized that this is only because the EVLA
antennas are not being flagged bad, or are being counted as
being on source before they really are.  All VLA antennas for
the same time do not make it through the data filler, meaning that
the Modcomps knew they weren't on source yet.

Other than this first-record problem, 13, 14, and 16 appear
to have performed quite well.  There were some closure
issues described in the next paragraph.

There are two closure oddities in the calibrator solutions that I would like
to understand.  The EVLA baselines show the typical positive
closure errors of order 5% or so, except that 13-16 IF B (RCP) has
closure errors of as much as +15%.  Similarly, 13-22 IF D (LCP)
has closure errors of -15%.  Inspection of the data shows that these
are not due to individual bad points or records (at least on the 10-second
scale), but that the correlator values are consistently high or low.
Thus there must have been something else going on.  It is hard to
imagine that it is just a coincidence that the baselines in question
involve either one or two EVLA antennas, but it is hard for me to
guess at what the cause might have been.

Jim