[evlatests] EVLA System Check

[Jim Jackson]

I just found antenna 18's T302 to be in an odd state.  I reinitialized the 
command values for the switches and solar attenuators.  The antenna appears 
to be in the array observing at L-band and the levels now look OK even 
though the switch echoes and monitors don't make sense.  I may have 
glitched a few things on 18 while doing this (about 1710-1715 local time).

Jim

At 04:27 PM 3/19/2007, Rick Perley wrote:
>     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.
>
>
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