[daip] [!14796]: AIPS - Unstable phases on the GBT

[James Miller-Jones]

James Miller-Jones updated #14796
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Unstable phases on the GBT
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           Ticket ID: 14796
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/14796
                Name: James Miller-Jones
       Email address: james.miller-jones at curtin.edu.au
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 17 September 2019 01:09 PM
             Updated: 17 September 2019 01:09 PM
           Reply due: 19 September 2019 01:09 PM (2d 0h 0m)
      Resolution due: 13 June 2022 12:00 AM (999d 10h 51m)

Hello,I have some HSA data from June 2014, which involved the GBT (plus the VLBA and the phased VLA; project BS228E/F).  The project is a phase referencing experiment to detect a very faint source.  My original data reduction could not get good results for Green Bank, which I had thought was due to poor weather at the site.  But last November, I received notification that the replacement LO synthesisers were causing phase jumps at every scan boundary, as reported at https://science.nrao.edu/facilities/vlba/proposing/news/.The message suggests that the use of PCCOR in AIPS might possibly be able to retrieve results from the GBT, even though self-calibration is impossible and there is no in-beam calibrator in this experiment.  I would like to try to retrieve something from the data, since without GB we do not have the sensitivity to detect our target (that was part of the justification for HSA observations in the first place!).  The instructions suggest consulting the PCCOR help pages, but from reading them, it was not entirely obvious to me how to correct these instrumental jumps between scans via the use of PCCOR, which seems more geared towards calibrating delays.Could I ask for some guidance in how to use PCCOR to correct for this effect (assuming that I can find GB pulse cal data in the PC table)?Thanks in advance,James Miller-Jones

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