[evlatests] Q-band performance

[Rick Perley]

    Q-band works remarkably well, but there are some problems...

    Antennas 13, 14, 16, and 24 gave good fringes.

    No fringes detected from 18. 

    Stability was as good as can be expected at this frequency! 

    Sensitivity:
   
       13 and 14 are near normal.  (Normal is not easy to define -- 
there is a very wide spread in sensitivity amongst the VLA  antennas, 
doubtless due to various issues with optics and receivers.  13 and 14 
lie within the VLA sensitivity envelope, but on the lowish side.  This 
doesn't worry me -- we surely have significant optics and surface 
corrections to make yet to get Q-band up to the required levels). 

    Antennas 16 and 24 are both quite weak:  Antenna 16 is about 1/3 of 
the anticipated sensitivity, 24 is down by about 50%. 

    It is easy to explain 16's result -- for reasons unknown, pointing 
failed for this antenna -- AT ALL BANDS!!!   Antenna 24 got a good 
pointing solution, so its poor sensitivity is due to other issues.

    I cannot check Tsys for these EVLA antennas -- all values in the 
tables are nonsense -- from 6 to 8 Kelvin.  VLA values are normal.