[evlatests] Array Status -- Friday Night Test

[Ken Sowinski]

On Sat, 8 May 2010, Rick Perley wrote:

>    The four-mode, three-times-around 'stress test' was run Friday
> evening.
>
>    The only changes from the previous day are:
>
>    1) The phase jumps peculiar to antenna 2 in IFPair A/C are gone.
> Its L301-1 was changed on Friday.
>
>    2) The peculiar lack of fringes from antenna 26C, seen only in OSRO1
> modes, has gone.  This antenna/IF now fringes normally in all setups.

I noticed this on Friday.  It began working again after we had
poked a lot at pieces of the correlator.  No explanation yet.

>    The remaining problems are as before:
>
>    1) There are an inordinate fraction of zeros.  In OSRO1 modes, about
> 14%, almost all of which strike the same set of antennas within ~ 30
> seconds of a Mode change.  (Since this program changes mode every 3
> minutes, this results in a high fraction of zeros/blanks).  In OSRO2
> modes, we see the additional characteristics that antennas 14, 15 and
> 16, in IF 'C', are totally blanked.  The resulting fraction of pure
> zeros is 24%.

We should not worry much about zeros associated with reconfiguring
the correlator until Sonja has deployed a new Confgiration Mapper that
tries to configure all the boards in parallel rather than serially.
We hope to see that this week.

>    2) Antenna 17 is very weak in RCP.
>
>    3) Antenna 12 is very, very weak in LCP.

Both these are only at C band.