[evlatests] AR603 this morning (3aug06): some odd ant. 24/X band behavior

[Michael Rupen]

A quick update on the ant. 24, X band, IF C problem.
- It shows up in several target pointings during the same fs scan as well,
   and also in a single "pointed" scan at the end of the run.
- Each occurence lasts 6-30 seconds.
- There are often associated "pretty lousy" data, occurring just before
   or just after the really horrible stuff, in which the amplitude is high
   on many but not all baselines.
- About 10% of the total data from this IF are obviously affected.

        -- Michael

On Thu, 3 Aug 2006, Michael Rupen wrote:

> AR603  3aug06  03:54-05:55 IAT
> ------------------------------
> mrupen  3aug06
>
> Quick & dirty report: looked at raw data only, no sensitivities etc. yet
>
> EVLA ant. 13,14,16,18,24 included
>
> Standard continuum, C X L bands (L band uses L1 setup)
> 3.3s averaging
> elevation 20-72 degrees
> mediocre weather (clear skies, API 9-20 degrees)
>
> Obvious problems:
> * Ant. 13, IF C, no fringes at any band
> * Ant. 16, IFs AC, no fringes at C band
> * Ant. 24, no data at L and C bands
> * Ant. 24, X band, IF C had two sets of ridiculously high amp. with constant
>  phase (-45 or 135 degs, depending on the baseline), during the same fast
>  switching scan.  Both involved the calibrator (rather than the target);
>  the first lasted two integrations (6 sec), and the 2nd lasted 20 sec (6
>  integrations).
>
> Other than this the raw data look reasonable.  I will send out a fuller
> report later today or tomorrow, if the gods are smiling.
>
>