[evlatests] Temporal phase drifts

Michael Rupen mrupen at nrao.edu
Tue Oct 27 12:46:29 EDT 2009


>    Vivek mentioned in the WIDAR Monday meeting that although phases now
> connect beautifully, there is some evidence of phase drifts.  I've
> checked this with the 6-hour C-band database that was taken on
> Saturday.  The results, based on using antenna 28 (N8) as reference:
>
>    Antenna 3's phase (both polarizations, all subbands) declines
> steadily by 60 degrees through the time interval.
>    Antenna 24's phase (both polarization, all subbands) declines
> steadily by 70 degrees throughout.
>    Antennas 8, 9 and 27 all have a similarly-shaped rise in phase by
> ~20 degrees, occuring over the final hour only.
>
>    All other antennas show zero drifts.
>
>    Antenna 3 is at E9, antenna 24 at W5, antenna 8 at N1, antenna 9 at
> E6, and antenna 27 at E3.  There seems to be no simple explanation for
> these drifts on the basis of array position.

Is this seen for any antennas in the simultaneous VLA data?

Have the antennas listed here shown drifts in (e.g.) previous VLA baseline runs?

         Michael



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