[evlatests] EVLA System Check

[Rick Perley]

    As noted earlier, I used the software time today for a number of 
tests. 
    Here I give the rough results of an EVLA 'system checkout'.  These 
were done with a continuum setup, which pollutes simple calibration, so 
no effort was expended here on sensitivity.  This is only for what 
works, and what does not.
    Observations taken with 410 msec averaging.  An attempt to use 
referenced pointing was made -- I haven't gotten the solutions from 
operations yet, so I don't know if this was successful. 

    A) Global Issues (affects all EVLA antennas, regardless of band). 

       24, IF 'A' was dead throughout. 
       24, IF 'B' has four clearly separated amplitude states, with 
amplitude ratios of 1.0, .83, .71, and 0.55. The most common state is 
1.0 (the strongest), the other three become less 'common' as the 
strength declines.  There is no phase effect. 
       24, IFs C and D showed the effect above, but much more rarely.  
Essentially, a few apparent dropouts. 

       EVLA phases looked good, in that no strong drifts were noted. 

    B) Band Dependent Problems.

    1)  L-Band.   Antenna 18 was dead.  All others worked (except 
antenna 21, which doesn't have a receiver).

    2  C-Band.   Antenna 26 showed very weak fringes -- fairly strong on 
IF 'B'.  (No fringes from 21 or 23, because there are no receivers). 

    3) X-Band.  All 9 antennas fringed stably!  However, antenna 21 A 
and C have two very different amplitude states, differing by a factor of 
2.0.  The fringes on these IFs are weak, even in the stronger state.  
21B and D look pretty good. 

    4) K-Band.  Ant 21 gave no fringes.  Ant 24 was very weak.  All 
others looked o.k. 

    5) Q-Band.  Ants 13, 14, 16 and 24 look normal.  Ant 18 is very 
weak. The others have no receivers yet.