[evlatests] C, K, Q bands last night.

[Rick Perley]

    From last evening:

    A) C-band

    16 out for wiring.  21 and 23 have no receiver. 

    No useable data from 26 -- and this antenna is claimed to have a 
receiver.  The Tsys values are in thousands of K. 

    Antenna 14 gave perfect data in the continuum, but was absent in the 
line data. 

    24C has multiple levels, as in all other bands. 

    The usual 'fast drops' are seen -- more at this band then at others, 
it seems. 

    Sensitivity was poor on antennas 17 and 13 -- for both, the listed 
Tsys is twice, or more, the expected values.

    B)  K-Band

    Referenced pointing was attempted -- and worked on antennas 14 and 26. 

    antenna 21 gave data, but no SNR.  Presume pointing, focus, or 
similar problem. 

    antenna 14 disappeared after the first record.  This happened at 3 
other bands, but is not an EVLA problem -- other VLA antennas did this 
too. 

    Amplitudes and phases of the remaining antennas were fine.

    Sensitivities:  Poor on all antennas except 26 -- for which 
referenced pointing worked.  Presume pointing is the problem.
   
    Tsys on antenna 23 claimed to be 500 K!  Something is not right, as 
all other antennas (including 14 and 21) clearly show the change of Tsys 
with elevation (due to atmospheric emission), but no such change is 
visible on 23.  This antenna has very poor SNR too, but only low by a 
factor of 3 to 4.  It should be more if the Tsys really is 500K. 
   
    C)  Q-Band

    Referenced pointing attempted -- and worked on 13 (only). 

    Sensitivies are very poor, except for antennas 13 and 24.  Again, I 
presume that pointing is the critical factor.   For these two antennas, 
gains/phases look reasonable. 

    Nothing else useful to report at this band.