[evlatests] report on AL703 from yesterday evening

[Claire Chandler]

Following is a report on AL703 from yesterday evening.  There are some 
phenomena to be concerned about, especially #6 below.

Claire

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3 hours at X-band, 3-second integrations.

1) There are amplitude and phase drop-outs on the EVLA antennas, plus
VLA antennas 27 and 28, on scan change, even though there was no source
or band change.  All the other VLA antennas just kept taking data through
the scan boundary (no 20-second set-up time!) and look lovely.

2) Data are mysteriously missing from all antennas for 10 seconds at
IAT~03:40:40, and the two integrations preceding this drop-out and
one following also have amplitude and phase problems on most antennas.
There is no note in the log of anything happening at this time.

3) There are amplitude and phase drop-outs on antenna 26, IFD.  Since
there is no way to tell whether this is happening for my (weak) target
source, the whole IF needs to be flagged for the entire observation on
this antenna.

4) The last integration of the last scan is bad but not flagged.

5) There is a surplus, bad, unflagged integration on EVLA-EVLA baselines,
followed by a 10 second gap, before good data on a scan begins.
The good EVLA-EVLA data begin at the same time that good data on VLA
antennas begins.  Is something being mislabelled or flagged incorrectly
somewhere on the EVLA antennas?

6) There are bad periodic amplitude variations on antenna 13, IFs A, C,
and D, and antenna 14 IFs A and B.  The period depends on the source
being observed.

7) The gains for antennas 11 and 19 are way off from where they should be.
Are the Tcals set correctly?

8) The calibrator amplitudes on antenna 11 declined steadily throughout
the observation.  Is the pointing determined yet for this antenna?

9) There are some nasty phase wraps but it is difficult to disentangle
weather from the system phase.