[evlatests] Modcomp-free flagging -- L-band.

[Rick Perley]

    The situation here is complex ...

    The antenna which are *actually* dead (and hence deserve flagging) are:

    ea18 -- all IFs
    ea23 -- all IFs
    ea13D -- dead as a doornail. 

    In addition, ea13B is very weak, but gives stable fringes.  Probably 
should be flagged. 

    Here is what actually got flagged:

    1)  ALL VLA antennas, for the last 8 seconds of the scan. 
    2) VLA antennas 6, 7, 10, 15, and 22, plus EVLA antennas 16 and 23, 
throughout the whole scan, on all IFs. 
    3) VLA antennas 1, 3, 5, 9, and 17, for part of the scan, all IFs.
       Much of what's noted in (2) and (3), above, is likely related to 
a long unwrap that took place.  The preceding P-band observation was of 
a source near the cable wrap limit, this L-band observation only a few 
tens of degrees in azimuth away (different source).  I had a 3-minute 
dummy X-band scan in between (and no valid data were recorded).  Nearly 
all of the 3-minute duration of this L-band scan is similarly flagged 
(and no source present).  But it is clear from the 'unflagged' data that 
all antennas were safely on source at least 20 seconds before the end of 
the scan.  The flagging noted above was during this interval. 

    Antenna 23 was correctly flagged, but antenna 18 was unflagged (and 
should have been) on IFs B and D.  Antenna 13, IFs B and D were not 
good, and were not flagged.