[evlatests] Report on AH939

[Rick Perley]

    AH939 was run, modcomp-free, in the morning of July 2.   Band = LL, 
Mode = '4', BW = 25. 

    Report on data quality:

    Antennas 6, 7, 15, and 22 are erroneously flagged.  Antenna 1 is 
mostly flagged, also erroneously.  (Note to users -- fill the data 
twice, once with flags applied, and once with flags off.  You can use 
the former file to properly flag the beginning of each of the scans of 
the latter). 

    There are no valid data for the first observation -- a calibrator 
located far from the target source. 

    The file is missing its calibrator data for four consecutive hours.  
However, this is almost certainly due to them choosing a calibrator on 
the opposite side of the zenith from the target source.  The antennas 
were very likely doing the 'half-rotation' dance, without enough time to 
reach the calibrator. 
    Fortunately for the users, the phase and amplitude stability are 
superb, so interpolating the solutions taken at the beginning and end of 
the run should suffice. 

    Antenna 13, IFs B and D are weak -- a known problem.  Data should be 
flagged. 

    Otherwise, this run went very well.