[evlatests] System Status from Yesterday's tests ...

[Jim Jackson]

We'll need to replace that synthesizer in antenna 2.  It is also 
still complaining about a bad heartbeat signal.  It's already written 
up in Mainsaver for that alert.

Jim


At 01:54 PM 5/6/2010, Rick Perley wrote:
>     The 'block of four' mode test that MPR made up to test
>multi-configurations within a SB proves to be a useful tool ...
>
>     This test was run again yesterday evening, primarily to see if the
>phase hopping associated with the L302 module swaps had been eliminated.
>
>     Results:
>
>     1) Phase Hops at scan boundaries are gone -- with a single, special
>exception.  Antenna 2, IFpair A/C, is hopping by 120 degrees, on scan
>boundaries -- but only when we were in the narrowest (31.25 kHz)
>bandwidth.  In reviewing my notes from the previous day's test, I noted
>that antenna 2, for that BW only, had two different 'hop values' whereas
>for the other BWs for that antenna/IFpair, the 'hops' were of a single
>size.  Hence, it seems clear that the phenomenon reported above has a
>different origin, one specific to that narrow bandwidth/observing mode
>(OSRO2).
>
>     2) Large fractions of blank data (pure zeros) remain.  As before,
>OSRO2 modes are missing all of antennas 14, 15, and 16 if IF 'C'.  All
>the observations (both modes, all BWs) show that some antennas remain at
>zero for up to one minute, following a mode change -- this problem is
>never triggered by a scan change.
>
>     3) Antenna 17 in RCP is very weak -- amplitudes low by a factor of
>about 4.
>
>     4) Antenna 12 in LCP is very, very weak -- fringes barely discernible.
>
>     5) Antenna 26, IF 'C', in OSRO2 mode *only* has no fringes.
>
>     6) All delays are less than 4 nsec.
>
>     7) The visibility amplitudes showed excessive short-time scale
>'jitter' -- of order 1%.  (Yes, I'm fussy).  As the winds were blowing
>about 25 mph (average), I'm guessing that this jitter is due to the wind
>-- visible even at 6cm with the sensitivity we now have...
>
>
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