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Date: Tue, 10 Apr 2007 11:51:09 -0400
From: Frank Ghigo <fghigo@nrao.edu>
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To: jbraatz@nrao.edu
CC: Lincoln Greenhill <lgreenhill@cfa.harvard.edu>, jcondon@nrao.edu,
        gbtobssum
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Subject: VLBI project BB231 at Green Bank
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We observed VLBA projects bb231e, bb231f, and bb231g
with the GBT.   They were observed at K-band, and the
array included the VLBA, the GBT, and Effelsberg.
There were a few difficulties.

April 7:  bb231e : started a few minutes late because the active surface
  had to be re-booted
    On schedule at 03:19 UT  instead of 03:15.
    -- off source 11:08 to 11:30 UT due to an AZ motor servo failure.
 
   The weather was not too good: cloudy with light snow,
   but the peaks looked ok, and the Tsys ranged from 35 to 60K.
    So probably it was reasonably sucessful.

April 8 : bb231f:
    Weather was more of a problem, snow flurries and cloudy.
    Had problems with getting good peaks early in the run, Tsys 40-60K
    Started late : on source at 03:32 UT  (should have been 03:15)
        after unsucessful attempts to get a good peak.
        The best LPCs were entered by hand.
    Things improved later on; after 06:00 UT the peaks look better.

April 9 : bb231f:
    Again started late, this time due to MCB communication
    problems with the receivers.  On source at 03:30 UT.
    Weather was a little better; overcast, peaks looked pretty good,
    Tsys about 50K

    12:50 to 13:37 UT - Mark5 recorder off line due apparently
    to a marginal power supply.  It was restored to operation
    after a reboot of the Mark5.  
    I am told that a low power supply can cause damage to the disks.
    After the re-boot, the remaining recording seemed to go
    normally, so I hope the disks were all ok.
    We are getting a new power supply soon.

The 4 disk packs used by these 3 runs have been shipped to Socorro:
NRAO-103
NRAO-139
NRAO-158
NRAO-082


-- frank