[evlatests] AN129 Report

[Rick Perley]

    AN 129 (X, C band 50 Mhz continuum, 10-second averaging) began at 
about 1AM this morning, and runs until about 11 AM.  I filled the data 
for an early look.

    In general, there are no serious issues.  Phases and amplitudes look 
fine.  The data should be fine for science. 

    Two antennas (10 and 17) are out of service for various reasons, but 
should return shortly. 

    Issues found:

    1) Global

    The 'last-10-second' problem is easily seen -- occurring at both 
bands, and only when the next scan is at a different frequency. 

    2) X-Band

    Only some minor flagging issues to report on.  Antenna 1 is being 
occasionally flagged bad, when the data seem just fine.  Antenna 9 gave 
perfectly zero correlation for one scan, but was not flagged. 

    3) C-Band

    Some more significant issues here. 

    Antenna 18 is giving giant 'pulses' at all four IFs.  The 
visibilities, about once per minute, leap up to a value 10 to 30 times 
too high.  This lasts a single (10 second) record.  It is seen only at 
C-band -- X-band is o.k. 
    Antennas 19 and 21, despite having no receivers, are commonly not 
being flagged.  This is easy to detect on a strong calibrator (no 
fringes), but not on a weak blank field.  Do we not have a foolproof way 
to detecting the absence of a receiver? 
    Antennas 13 and 14 were occasionally being flagged -- sometimes 
correctly, sometimes not.  No simple pattern is detected.