[evlatests] some steps forward and backward

[Ken Sowinski]

As Rick reported we seem to now have the EVLA antennas
positioned consistently with the VLA and the large phase
winds we were seeing due to antenna position errors are
now much reduced.  In addition to his reports of data
quality I can add that 18C now looks normal.  As recently
as last Thursday it still had funny phase behavior.  Much
was done to it yesterday and this morning so we don't know
the cause; my feeling is that resetting the DTS mat have
fixed it.

The funny data "dropouts" Rick reported for antennas 13 and 14
are also there at K band and much stronger.  Rob told me today
that he suspects a problem with the L301-1 at antenna 13 because
it reports brief out of lock episodes.  This is not inconsistent
with the amplitude jumps Rick and I see.  I understand that Rob
will try to replace that L302 Wednesday.

Pointing is a fiasco.  K band and Q band barely work at all, with
or without referenced pointing.  Either I misinterpreted the
pointing measurements made Sunday or referenced pointing is no
longer doing what we expect.  I did two things.
1.  I tried a sequence of pointing scans at X, Q and K bands
applying referenced pointing for Q and K, but not X.  There
were no pointing solutions for Q and K and hardly any power
at the ons.
2.  In frustration I tried a more simple test: X band pointing
followed by Q and K band scans (no pointing) with referenced
pointing applied.  Again no luck.  When I changed to a K band
script without referenced pointing the response improved for
two of the three antennas.

The rest of the time will be spent placing two small rasters
on 3C84 at K band: one with referenced pointing and one
without.  The goal is to see where the beam is and if it is
differently displaced in the two cases.


Before Thursday I will examine the Sunday pointing results
again and try to reconcile it with today's measurements.


If anyone is interested there was a long integration using
antennas 14 and 16 at C band starting about 2100 and going
to almost 2200 IAT.