[evlatests] EVLA high frequency efficiency

[Rick Perley]

    Using models of Venus provided by Bryan, and accounting both for 
atmospheric opacity and antenna beam attenuation, I have determined the 
efficiency of antenna 24 at K, Ka, and Q bands.  The table below 
summarizes the results.   The third column is defined as Tsys/effic, in 
dry cold weather, at the zenith. 

Freq.   Efficiency  Teff
----------------------------------
18440       0.55        88
18952       0.55        75
23560       0.53        75
25608       0.52        70
26120       0.47        85

26232       0.48        119
28024       0.48        85
33160       0.43        96
38064       0.34        147
39600       0.32        208

40368       0.30        206
41136       0.30        189
43440       0.33        181
48048       0.23        354
49584       0.17        788

All values -- except the two highest frequencies in Q-band -- meet or 
exceed project requirements.  I have no doubt that the Q-band results 
can be improved with refined optics and antenna re-alignments.