[evlatests] Near-term use of EVLA antennas with VLA observing array

[Jim Ulvestad]

                                          February 2, 2006



TO:      EVLA and VLA staff

FROM:    Jim Ulvestad, Mark McKinnon

SUBJECT: Near-term use of EVLA antennas with VLA observing array



     After consultation with the servo group and other VLA site
personnel, we have decided that we will not permit EVLA antennas
(specifically 13, 14, and 16 at present) to be used as part of the
VLA observing array except during normal weekday working hours.
The incidence of ACU MIB errors and antennas being driven into their
stops is too frequent, and the possible risk to antennas is too
great for the minor benefits of exercising the antennas.

     For this coming weekend, this specifically means that the EVLA
antennas MUST NOT be included in the baseline and pointing runs on
Friday night through Saturday morning, and must not be used in any
of the astronomical observing over the weekend.  Instead, the EVLA
antennas should be stowed, with the brakes set, before the members
of the servo group leave for the weekend.

     During the daytime next week, the EVLA antennas may be used,
for example, during AR570 and Polarization Calibration on Monday,
and during the various software tests during the week.  Again,
they will need to be stowed by close of business on Friday, February 10,
and also should be stowed in the evenings unless there are EVLA
personnel actively working on the antennas.  The restrictions outlined
in this memo will remain in place until Monday, February 13.
We will plan to re-visit the status of these antennas again at the
EVLA Coordination and Test Meetings on that date.