[evlatests] EVLA Status, Wednesday 9 Jan

[Rick Perley]

    Following the 2-day maint period, I checked EVLA performance with 
the usual stress test. 

    Short Version:

    The EVLA (and VLA) are working better than I've ever seen it 
before.  (And I hope somebody mentions that at the NRAO Town hall 
meeting ... hint, hint, hint).

    All antennas working well at all bands except: 

                  a) antenna 1 at Q-band,  (No receiver yet, i guess)
   
                  b) antennas 1, 13, and 16 at P-band.  (No rcvr in 16, 
13 and 1 are still broken). 

                  c) VLA antenna 2 is out of the array, with a bad modem. 

                   d) The only antenna with significantly low 
sensitivity is antenna 25 at K-band -- sensitivities low by a factor of 
about 5 in all IFs. 

     Longer Version:

    A)  The usual bad initial record is seen on all scans, except at 
X-band, where it follows an x-band referenced pointing. 

    B) The file was in durations, and the last scan was ended earlier 
than it should have been -- instead of being 80 seconds long, it was 22 
seconds long.  We lost about a minute. 

    C) The usual SSDs (short, shallow drops) were seend. 

    D) P-band (sigh):  Antenna 1 still giving essentially no fringes, 
and is flagged.  Antenna 13 is flagged in IF#1, but not in IF2 -- but 
should be!  Antenna 23 is unflagged in IF 2, and shows very poor data. 
    All amplitudes were very ratty in IF 2 -- I'm pretty sure this is 
RFI.  Other than these issues, the rest of the antennas gave acceptable 
sensitivities. 

    E) Antenna 14 at X-band in LCP is about 20% weaker than it should 
be.  Likely a high Tsys ...

    F) Q-Band gave excellent fringes on all antennas except #1.  This 
despite a high (20 mph mean) wind.  Referenced pointing was successful 
in getting the antennas more or less on source.  This was for the first 
scan.  On the second scan, referenced pointing failed, and the antenna 
were clearly well off the beam and moving about!