[evlatests] Phase Spinning, and more.

[Ken Sowinski]

>     c)  You would expect that there should be a reduction in the
> correlation coefficient during those scans with the phase winding,
> compared to those where the phase is not winding.  *** THIS IS NOT THE
> CASE!!!*** The 400 msec amplitudes are the same whether the phases are
> rotating or not.  Hence, the phases are not really rotating during the
> 400 msec integration.  This suggests that the problem may be generated
> within the Modcomps, rather than the EVLA antennas.  Ken can imagine a
> scenario wherein this can happen for IFs B and C, but not A or D.  But
> the lack of correlation degradation is seen in all IFs.

My imagined scenario posited that the RT phase correction was enabled 
in the Modcomps and the VLA RT phase monitor point sometimes misbehaved
in such a way as to explain this.  As Rick says this would only affect
IFs B and C, and in any case the RT phase correction is disabled in the
for EVLA antennas.  We need another suggestion.