Difference between revisions of "2019 May"

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(Created page with "[http://www.ovsa.njit.edu/wiki/index.php/Expanded_Owens_Valley_Solar_Array#Observing_Log Back to Observing Log] == May 09 == '''11:03 UT''' The data from 19:00 UT yesterday u...")
 
(May 09)
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== May 09 ==
 
== May 09 ==
 
'''11:03 UT''' The data from 19:00 UT yesterday until now are no good.  Yesterday Kjell replaced the 800 MHz clock derived from the signal generator with one from a new Valon 5009 Synthesizer.  Although the data seemed to be okay, I could not see any coherence in the phasecals or refcals.  That prevented me from getting a delay correction.  This morning I checked the delay using a communication satellite and discovered that two antennas, 8 and 14, had extremely high delays, about 300 ns!  I rebooted the correlator this morning and rechecked, and now they are fine.  I have seen this strange behavior once before, so I can only surmise that occasionally on a reboot of the correlator we can get really wacky delays on some digitizers (or ROACH channels--maybe not the digitizer itself).  This suggests that we really need to make a quick observation of a satellite after a reboot in order to do a sanity check on the delays.
 
'''11:03 UT''' The data from 19:00 UT yesterday until now are no good.  Yesterday Kjell replaced the 800 MHz clock derived from the signal generator with one from a new Valon 5009 Synthesizer.  Although the data seemed to be okay, I could not see any coherence in the phasecals or refcals.  That prevented me from getting a delay correction.  This morning I checked the delay using a communication satellite and discovered that two antennas, 8 and 14, had extremely high delays, about 300 ns!  I rebooted the correlator this morning and rechecked, and now they are fine.  I have seen this strange behavior once before, so I can only surmise that occasionally on a reboot of the correlator we can get really wacky delays on some digitizers (or ROACH channels--maybe not the digitizer itself).  This suggests that we really need to make a quick observation of a satellite after a reboot in order to do a sanity check on the delays.
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== May 10==
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'''12:56 UT''' The delays have been updated this morning prior to today's calibrations.

Revision as of 12:58, 10 May 2019

Back to Observing Log

May 09

11:03 UT The data from 19:00 UT yesterday until now are no good. Yesterday Kjell replaced the 800 MHz clock derived from the signal generator with one from a new Valon 5009 Synthesizer. Although the data seemed to be okay, I could not see any coherence in the phasecals or refcals. That prevented me from getting a delay correction. This morning I checked the delay using a communication satellite and discovered that two antennas, 8 and 14, had extremely high delays, about 300 ns! I rebooted the correlator this morning and rechecked, and now they are fine. I have seen this strange behavior once before, so I can only surmise that occasionally on a reboot of the correlator we can get really wacky delays on some digitizers (or ROACH channels--maybe not the digitizer itself). This suggests that we really need to make a quick observation of a satellite after a reboot in order to do a sanity check on the delays.

May 10

12:56 UT The delays have been updated this morning prior to today's calibrations.