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Good data from 04:46 UT onwards
failure of the main communication links from the control computer to the antennas, and no commands are going to the antennas. This happened at ~ 06:30 UT, just about the time the cycle on the two sources J2225-0457 & J2218-0335 came to an end, and the one on J2348-1631 & J2354-1513 was to begin
Observing Log for VLBI test of 8 Mar 2011
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Participating telescopes : GMRT + ATCA + Mopra
Configuration at start of expt : RF band = 1390, LO-I = 1330, LO-IV = 60, LO-V = 140 (& 165), IF BW = 16
Test on 3c468.1 : fringes seen on all working antennas ; weak fringes on C03.
Antennas selected for VLBI experiment : C00, C01, C02, C04, C05, C06, C08
(note : C04, C05, C06, C08 connected to BB monitor port o/p (both pols)
0x:xx : Fringes still seen on ALL working antennas in GSB, except C08 !! no LTA file recorded !!
Slew to source 2253+1608 : need to go from outer to inner =⇒ 10 mins delay !! Fringes seen in GSB.
Meanwhile, checked disk mounting and remounted the data recording disks.
Stopped real-time mode of GSB : hltndas.gsb
Started raw-dump mode and did a short test : 09:57:00 onwards, for 100 blks
Ready to start actual run : already about 30 mins behind the schedule ! =⇒ edited the cmd file accordingly to drop some of the initial pointings
Sources to be done today are (all are being taken from main GMRT source list) :
J2253+1608 (named 2253+161 in the GMRT source list) 10 Jy @ 20 cm; UVMax 7 kL
J2218-0335 (named 2218-035 in the GMRT source list) 1.0 Jy @ 20 cm; no UVlimits
J2225-0457 (named 2225-049 in the GMRT source list) 5.7 Jy @ 20 cm; UVMax 45 kL
J2348-1631 (named 2348-165 in the GMRT source list) 2.7 Jy @ 20 cm; UVMax 15 kL
J2354-1513 (named 2354-152 in the GMRT source list) 1.0 Jy @ 20 cm; UVMax 30 kL
changed # of blocks in run_rawdump.csh of readSHM to 7200 (for 30 mins).
Recording #1 :
start at : 2011 03 08 09 59 00 ; stopped at : 10 24 00 raw_voltage1.vlbi_8mar_1.node0.scan0 should have been on 2253+1608 since the beginning, but had problems with the cmd file and had to fix things (cmode 0 vs cmode 1 -- latter needed for fixed time command execution !!)
finally, useful data on 2253+1608 is only from 10:12 or so onwards ! first change of source in sync with schedule is at 10:16:00 to J2225-0457 after that things are in sync...
typical settling time for the antennas to be on source is 30 sec ==> good data can be said to be available from 30 sec from nominal start minute, for each scan.
killed at 10 24 00, at end of scan on J2218-0335
Recording #2 :
start at : 2011 03 08 10 25 00 ; stopped at : 10 53 30 raw_voltage1.vlbi_8mar_2.node0.scan0
reached on source (J2253+1608) at 10:27:00 but immediately had problems due to changes made in cmd file !! fixed and restarted cmd file ; back on source (J2253+1608) at 10:29:30 ==> 4.5 mins of good data till change of source to J2218-0335
killed at 10:53:30 (while on J2218-0335 scan)
Recording #3 :
start at : 2011 03 08 10 54 00 ; stopped at : 11 24 00 raw_voltage1.vlbi_8mar_3.node0.scan0
first source is J2225-0457 (usual 30 secs safe time from min value) last source is J2253+1608 (stop is in the middle of this scan)
Recording #4 :
start at : 2011 03 08 11 28 00 ; stopped at : 11 58 10 raw_voltage1.vlbi_8mar_4.node0.scan0
first source is J2218-0335 (on src is 50 secs after start!) last source is J2225-0457 (stop is in the middle of this scan!)
Recording #5 :
start at : 2011 03 08 12 00 00 ; stopped at : 12 31 10 raw_voltage1.vlbi_8mar_5.node0.scan0
first source is J2218-0335 (on src is 30 secs after start)
at around 12:05, commh system failed ==> no commands going from online to antennas !!
last source is .....
observation aborted; took about 1 hour of debugging for the problem to be identified and fixed. Resumed observations from 13:14 onwards.
Recording #6 :
start at : 2011 03 08 13 14 00 ; stopped at : 13 30 30 raw_voltage1.vlbi_8mar_6.node0.scan0
first source is J2354-1513 (already on src at start!) last source is J2348-1631 (stop afer end of the scan)
Observing run over !!
