[evlatests] June 12, 2006

[Ken Sowinski]

Another attempt was made to examine phase behavior.  The
weather early today ws reasonably good and we were able to
see that there was still a sawtooth in phase with a period
of 10 seconds in 13AC, but not BD.  This is attributed to an
error I introduced into the executor for testing which was
not removed before the SW update by Rich last week.  There
is no evidence that the L302s in antenna 13 are misbehaving
except for the known 10 second amplitude glitch.

The AC L302 in antenna 16  went into its catatonic state
again today.  Several (perhaps 3) reboots made no lasting
impression.  There must be something wrong with that module
or slot; I cannot remember the last time I had this kind of
trouble with any other L302.  Perhaps some swapping in the
aid of diagnosis is in order?

L band at antenna 13 is in good shape.  Relative G/T was measured
and 18 is clearly better than the other EVLA antennas.  As
expected, EVLA antennas are worse than all VLA at high elevations
(3C84, ~80 degrees) and EVLA better than all VLA antennas at low 
(3C273, ~35 degrees) elevations.  Perhaps it is time to gear up
for a systematic attempt at sensitivities again.  I suggest that
we wait till referenced pointing is understood so that we can
include K and Q band without having to worry about pointing.

Progress was made on an evla focus finding function.  It more
or less works, but it was found that the Modcomp equivalent
starts the focus cycle at the beginning of a scan rather than
when the antennas are on source so synchronization is not
reliable.  A survey was made over all bands for all EVLA
antennas and the only significant change was about 1.8 cm
for antenna 13 at C band.  The results at K and Q band were
not very convincing.  I intended to see how Flagger interacts
with focus cycling but ran out of time before that could be
done.  Perhaps tomorrow.

Rich managed to confuse himself and me trying to get an ACU
stow command to be accepted the antennas.  It seems to take
two stow commands in a row to get the antennas to stow.  The
first takes it out of DPM, but it does not go to the stow
elevation until a second stow command is sent.  Experiments
with VLA antennas were inconclusive.  More work, and thought,
is needed tomorrow.