[daip] [!11028]: AIPS - problem VLBI data averaging over IFs

[Eric Greisen]

Eric Greisen updated #11028
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       Staff (Owner): Eric Greisen (was: -- Unassigned --)
              Status: Closed (was: Open)
           Reply due: - Cleared - (was: 28 September 2017 08:36 AM)

problem VLBI data averaging over IFs
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           Ticket ID: 11028
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/11028
                Name: Gisela Ortiz
       Email address: g.ortiz at crya.unam.mx
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Closed
            Priority: Default
      Template group: Default
             Created: 20 September 2017 09:23 PM
             Updated: 13 November 2017 05:28 PM

Apparently this ticket did not get a formal answer.  You need tomake sure that your data are well calibrated.  Averaging each baselinesort of looks okay in POSSM.  But when one plots phase vs time forsingle IFs the phases often scatter over -180 to 180.  This isparticularly true for LL at the later scans in baseline 1-2 but is truefor RR and LL in baseline 1-3 and so forth.  If phase is not wellcalibrated, averaging will destroy amplitude.  AIPS handles 90 IFsin general so the 32 IFs are not the problem.I also fixed issues affecting ANTAB and APCAL.Eric Greisen


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