	Table 1:  AIPS weights -- proportional to (effic/Tsys)**2


               13               14               16		18
Freq  IFP   R      L        R       L         R      L       R     L
-----------------------|-----------------|---------------|-------------
1275  AC  133     120  |   130     130   |   125    110  |  110   130  |
1310  BD  140     110  |   145     150   |   100     65  |  135   135  |
1340  AC  105     115  |   130     110   |   115    100  |  120   140  |
1370  BD  115     104  |   128     135   |   105     65  |  135   145  |
1410  AC   75      85  |   115      95   |    95     95  |   95   110  |
1440  BD   77      70  |   100     105   |    80     30  |  120   120  |  
1470  AC   59      55  |    87      65   |    80     70  |   90   100  |
1510  BC   53      45  |    78      86   |    70     19  |   73    93  |
1565  AC   55      53  |    60      20   |    74     71  |   65    68  |
1590  BD   70      62  |    70      75   |    85     60  |   60    67  |
1620  AC   50      50  |    50      20   |    60     60  |   56    44  |
1670  BD   50      40  |    70      78   |    68     33  |   56    68  |
1706  AC   36      38  |    54      xx   |    70     68  |   64    60  |
1750  BD   25      22  |    58      62   |    69     18  |   26    58  |
-----------------------------------------------------------------------


Table 2:  Backend Tsys values -- adjusted for Tcal
 
               13               14               16
Freq  IFP   R      L        R       L         R      L
-----------------------|-----------------|---------------|
1275  AC   43      42  |    39      44   |    41     37  |
1310  BD   50      57  |    34      33   |    41     44  | 
1340  AC   32      29  |    34      35   |    38     36  |
1370  BD   50      54  |    31      30   |    36     40  |
1410  AC   42      36  |    34      38   |    40     37  |
1440  BD   57      57  |    33      30   |    41     49  |
1470  AC   52      49  |    35      37   |    43     40  | 
1510  BC   53      57  |    30      33   |    37     53  |
1565  AC   44      43  |    33      45   |    34     33  |
1590  BD   50      51  |    32      30   |    38     42  | 
1620  AC   47      41  |    38      53   |    36     34  | 
1670  BD   51      55  |    32      28   |    34     35  | 
1706  AC   55      49  |    35      89   |    38     34  |
1750  BD   74      73  |    39      33   |    39     45  |
----------------------------------------------------------

The typical best VLA AIPS weights values were

1275	80 - 100
1310	80 -- 100
1340	100 -- 120
1370	100 -- 120
1410	90 -- 110
1440	90 -- 110
1470	80 -- 90
1510	70 -- 90
1565	50 -- 60
1590	80 (hard to tell -- lots of RFI)
1620	50?  (RFI)
1670	80 -- 90
1706	70 - 90
1750	widely variable.  Most VLA antennas are in single digits.  


We see from this that the major loss of sensitivity with increasing
frequency is seen in all EVLA antennas.  But this is also seen in VLA
antennas, although with considerably less amplitude.  (Ignore the 1565
to 1620 Mhz results -- RFI has made these unreliable).

Although I have considerable faith in AIPS weights as an indicator of
sensitivity, I think we'll need to confirm these results with real
noise histograms.  Perhaps we can arrange this tomorrow or Thursday.


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